Need Help FAST What Want Wrong

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bruce119

bruce119

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Franklin, NC, USA.
Need Help FAST What Want Wrong

Here is a picture of some blanks I did last night. Notice the 2 on the left look good the 2 on the right has a shimmer like some air just on the surface.

What I did. First off I am using Alumlite Crystal Clear resin. I have been using this resin with excellent results. See my Birch Bark blanks. Any way I just got a large batch of snake skins freshly tanned from a suppler that deals with a lot of pen makers. Most the scales were removed I removed all the rest no scales. I cleaned them with regular 91% alcohol. Then CA them to a blacked tube. They set in a pressure pot all night 15 hrs at 50psi. When they came out this morning they looked great. Really good just now I looked at them and the two you see on the right developed that shimmer air look to them.

So what went wrong. All I can think was maybe not cleaning them good enough and I got a reaction. The skins are fresh and still have a wet greasy feel to them. Maybe I should have used denatured alcohol or something else. I just wiped them down maybe I need to soak them and really clean them better.

I'm sure some else out there like Don or Curtis knows just what I'm talking about. I don't really want to many failures and haven't had a problem like this before. I have 500" of skins I got to get this fixed.

BadBlank2.jpg


BadBlank1.jpg


SnakeSkinBlanks.jpg


Please help
Thanks
Bruce
 
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I am hoping to get some one who has had exsperance with this. These come from a supplier I know that others hear use. I problay need to to clean them better maybe denatured alcohol I used isopropyl 91%. But I sure would like to hear from exsperance.
 
Bruce,
I don't use alumalite(I cast with PR) but guess what? I have a drawer full that look exactly like those. It is air trapped in and around the scales, not just under those clear scale flaps or it is some kind of reaction of the curing agents with the resin. I've had them do that when I was casting blanks in blocks. One blank would do that and the rest were fine. Other times, all of them would be like that. Sometimes just on one side or just on one end. And, as happened to you, they look fine when removed from the paint tank, but later they develop that silvery shinny look and sometimes it is just a dull crud that developes. Join the club. I wish I could give you a definite answer. I know of your frustration. I know of spending a couple or three hours getting them ready to cast and all or some of the blanks go south. But, I'm glad to know that it happens with alumilite also. Here is what I've been doing that has cut down on this problem considerably.
(1) Clean off all the that oily residue that is on the skins. I do not remove the scales.
(2) I've painted the skins with acrylic fingernail polish or CA and that seemed to help but I was still having the problem from time to time.
(3) I now paint uncatalyzed resin onto the skins as I put them into the molds(gadget's silicone ones). I don't slather it on, but try to get a good coating on the skin. I let is set for about 30 minutes or more and it seems to soak into the skins and displace any air that is in or on the skin or scales. I then cast as usual. I don't know how this would be done with alumilite. Maybe painting some of one of the parts onto the skin will work...but I don't know that. It works fine with PR.
(4) I no longer use vacuum to degass the resin, but use an ultrasonic jewelery cleaner instead. I think using the ultrasonic cleaner has helped the most along with #3. I rarely have this problem happen any more....not for the last 6 months or so.
(5) Using gadget's silicone rubber molds...but it was still happening but got better after doing #3 and #4.

I am going to remove the scale flaps on the next blanks I cast and see how that works for me.

As I said earlier, Join the club. I know it is frustrating. Casting snake skins is not 100% successful...but it is getting more so for me. I'm having fewer failures and I've shared the 4 things that I think have help most in solving this problem for me.

Good luck and email me if you think I can be of any further assistance.

Do a good turn daily!
Don
 
What's really odd is it look great when they first came out after curing 15hrs. Then that shimmer developed during the course of the day. And I jusnoticed this evening. I am glad I didn't do a whole bunch. [B)]
 
Do You think soaking them in denatured alcohole over night mite help get the greasy feeling out. Maybe it's some type og glserin they use. But maybe soaking them them would get it out and dry them out. Do you think extended time soaking will harm the shinks ???
 
You sure did a great job with the ones on the left!! Do you remember which order they were poured? Maybe you should label the wood with 1 through 4 and see if it has to do with the order in which they are actually cast. Maybe the last ones the material has already begun to set and can't expel the air as well. Just a thought. I do think Don's suggestion of painting them with a bit of material before pouring and the ultrasonic vibrator do make good sense. Good luck. I can't wait 'til they go on sale. The driftwood you sold me made some beautiful sierras.
 
Bruce,
I'm not sure who you are directing these questions at but I'll answer them. I'm sorry if they are for someone else. I do not soak them but I have soaked them and it does not harm the skins. I just wipe the off lightly with a damp cloth. I also glue on the skins and wipe them down and leave them until the next day. Maybe it is the CA outgassing as it totally cures. But waiting until the next evening to cast may have helped also along with the other things I mentioned in my previous post.

I have had as many as 12 sets of blanks do this...bummer...big time.

I cast 3 of gadget's molds at one time, so waiting a day or two is not a problem...I make them up in a couple of evenings then cast the evening after I get the last ones ready.

don't know what else to add.

Do a good turn daily!
Don
 
Bruce, One of Dons suggestions is to me the most important if you want no air under the scales. I rub down all my skins after they are glued to the tubes with med CA, this seems to have helped on 90% of my cast. You will see that you still will at times have a batch fail, don't ask why it just happens. Don and I have discussed this and neither one of us has a reason as to why.So that being said just charge it up to expence of doing business.
 
Perhaps the CA out gasing mite be something. I did glue and cast pertty Qick. The order I don't think is an issue. I can get them in the pot and under pressure in less then 2 1/2 mintues. I mite try soaking a skin overnight in denatured alchol. I would think this would clean the skin and elimiante any water. I did skins before and not had a problem. These are very fresh taned skins maybe there's a lot of mosture in it. I know you guys use him he's not going to be around much longer due a disabilty. He was the one who said to remove the scales.

It is strange how 2 came out fine and the outher 2 failed. Same skin the 2 good ones were closed to the head. The only thing I mite have done differantly is maybe cleaning. I mite have wiped the first 2 down a little more thoughly I don't know.

I am not directing these questions to anyone in perticular. Just any one who has had exsperance. I am trying to eliminate the guessing game. I know Curtis use Alumlite and is a big supporter. I thought he mite have some input. I mit PM him and ask him to take look at the thread.

I will keep you posted on my progress. This is going to delay the sale a bit. I will get this down pat. That's the way I am I will figure it out and fix it. I just hope sooner than later.

I don't know about coting the outside with CA. I would afriad it would give it a shine. I know if I get too much CA on my Birch Bark I can see the shine it's not too bad but I know it's there.
 
I recently made up some bottle stopper blanks with items embedded in clear resin. One item has a "lip" around it, and that captured an air bubble as I poured in the resin. Cured for 24 hours at 60 PSI. Took it out of the pot, it looked great! As it sat, the air bubble fought its constraints and slowly made it out and past the lip and upward on the object. So it now has the shimmer look on part of it like your snake skins do. The full shimmer effect took about a week to show up, so my guess would be trapped air in your cast. Try the suggestions given for removing the air from the skin before it is cast and that should help.
 
Bruce,

Sorry I have not been on sooner. I have had a busy day and have just now had time to get on since early this A.M..

I really can not add anything at all to the snake skin discussion since believe it or not, I have never cast a snake skin! I have done fish skin in Alumilite with no problems but I also tanned that skin myself so I knew what was on it. That said, I can possibly offer some suggestions as far as Alumilite goes.

First off, with Alumilite I WOULD NOT paint the skins with part A or part B of the resin. I know Don has good luck doing this with PR but PR is not a 2 part system that depends on the proper ratio and mixing of the components. I have had cactus blanks ooze days later when I fist started and finally realized it was because I was not thoroughly mixing the components. I believe coating the skins first would cause similar problems. I guess if you have plenty of resin and skins you certainly could try it and see, though!

CA over the entire skin would be something I would try. I would also try shellac since it is commonly used as a sealer that will seal over just about anything. It might be easier to work with. With either one, though, I would let it cure for plenty of time to make sure it is not off-gassing something, causing a slight separation between the skins and the cured resin.

Other than this little bit of pretty much worthless information, I really can not offer anything else. It does not sound to me like a resin problem since it happens with both PR and Alumilite. Sorry I can not be of more help!
 
Sorry I didn't mention that I leave my blanks overnight after coating with CA to off gas.
Originally posted by OKLAHOMAN

Bruce, One of Dons suggestions is to me the most important if you want no air under the scales. I rub down all my skins after they are glued to the tubes with med CA, this seems to have helped on 90% of my cast. You will see that you still will at times have a batch fail, don't ask why it just happens. Don and I have discussed this and neither one of us has a reason as to why.So that being said just charge it up to expence of doing business.
Click to expand...
 
I won't (i.e. can't) cast wrapped tubes with Alumilite. I worked and worked at trying to cast labels in Alumilite and could not do it without getting the air like you. I tried pressure ranges from 18 - 60 psi. The tubes would come out of the pressure pot looking fine. The next day there was an air gap. PR shrinks. I think Alumilite might expand slightly when it comes out of the pressure pot and release from the tube.
 
So what do you otheres use when you cast. I have epoxy, silmmar 41 & the Alumilite.

The epoxy is good but exsenseive takes long to cure turns easy.

The slimar 41 is cheap a little finicky with the catyalast. I have trouble getting it to set. Then it is very hard and prone to chipping.

The Alumilite is easy to work with turns real easy. I use it with my birch bark with bad side affects. But then the bark is hard.

I see your point then maybe because the skin is soft and plyable it moves after/during the curing process. So like outhers said maybe the coating of CA mite be the answer. It would put a hard coat over the skin so there woyuld be no movement creating seperation.

I will get this figured out I want to make the Alumlite work. It's far easyer to turn and it works fine with my birch blank never had a failuar.

Bruce
 
Bruce, I use PR that I get from Composite one and have not had the problems you speak of it being very hard and prone to cracking. As far as it being finicky with the catylist I use 3 drops per once, nothing finicky about that but if you were to use to much thats when the pr will become brittle and crack. Also IMHO PR has a better finish than Alumilite and Epoxy yellows, the down side of PR is the odor and yes you some times have to wait for it to fully cure but if you have a toaster oven in you shop that you use for powder coating just put the blanks in the oven set at 150 degress for 30 min. or so and this speeds up the drying of the tackyness. Hope this helps.
 
I keep reading from several members about problems with PR setting up, or not setting up. I read about it being such a pain (you know where) to calibrate the amount of catalyst. I must disagree with these statements. I, as Roy also reported, use 3 drops of catatyst (per ounce of PR) and I've never had a clear cast (most all I do is snake skins) not cure. It is not hard and brittle, it turns like butter coming off in long ribbons and I too consider the finish to be better than alumilite. I've not had any brittle blanks and never had a blank ruin while turning by flying apart. I get a better shine and polish than I can get with alumilite and I have followed the finishing instructions given on the casting forum here. Just my results using a perceived inferior casting medium. I suppose Roy and I will continue to do what we are doing.
Do a good turn daily!
Don
 
Don what type of PR are you using. I tried slimar 41 and the instructions tell you to use a pretty lot of catalyst. And I have read that the extra catalyst will make the blank brittle.

I believe I think don't really know though that the mold effects the curing process. Such as I think you use a tub or container that holds a certain amount of volume. You use say 3 drops. Now I have the same volume but smaller individual molds that I got from gadget. Am I making sense. I know if I make a big cup of PR it gets hot and cures fast if I take the same mix and spread it out in a thinner container it will not cure the same. Is that making any since.

I would like to give PR another chance it does cost less.

Your thoughts
 
A little while back I took a look at very thin slices under the microscope of a snake skin cast very similar to your failure. What I saw was irregular shaped voids, not the spherical type you would get from dissolved gas coming out of solution, but ones that could be generated by the resin not wetting the surface of the skin. I think that what was happening was that portions of the skin had high amount of glycerine which didn't allow the resin to bond to the skin surface and as it cured, the surface tension pulled it away or there was some shrinkage and again because it wasn't bonded to the skin, a void appeared. The off color comes from light refracting in this irregular void.

Alot of good ideas are above to minimize this effect. Don's method of soaking in uncatalyzed PR allows the surface to equilibrate. Although it takes me a little longer, after gluing to the tube I paint the entire surface of the skin with thin CA using a nail for a paintbrush until the entire surface is hard. I don't have nearly as many under my belt as some of these folks, but so far so good.
 
I used Silmar 41 the last 3 years and had great luck with it. I know what the instructions say but the more catalyst I used the less success I had. I started backing off of the catalyst settled at 3 drops. It cures fine, takes a little longer, is not as brittle, and turns great. The instructions for all of the brands I've used say to use way more catalyst than I use.

I've just opened my first 5 gallon can from Composite One and I like it even more. It may just be my imagination but I really think it does a better job. It seems to be a little thicker, or it is just a little colder now. Anyway, I like the result I've had with the first two casts from it.

I was using 6 drops and casting in a small container that was just large onough for one set of tubes. It worked fine. I then started casting in a large plastic cake pan that held 7 sets of tubes and 16 or 18 ounces of resin...depending on the tube size. The castings were not predictable...several failures. It was the heat. The casting was larger, the heat was greater and it could only dissipate out the top exposed surface and I think it could not dissipate quick enough. I had one cast that the snake skins totally dissappeared...only brass tubes left. I may have miscounted the catalyst... Anyway, that is when I started backing off on the catalyst and settled at 3 drops per ounce and stayed there when I purchased gadget's silicone rubber molds. The resin is still curing fine and I'm having no problems. When I play with casting and try to make the ribbons I pour the resin onto a piece of glass and spread it thin it takes a long time to cure but it does cure. It may take as long as a day or so for the thin layer to get completely hard...but it does.

Good luck...this dialog has been interesting and I hope helpful to you and others.

Do a good turn daily!
Don


Originally posted by bruce119

Don what type of PR are you using. I tried slimar 41 and the instructions tell you to use a pretty lot of catalyst. And I have read that the extra catalyst will make the blank brittle.

I believe I think don't really know though that the mold effects the curing process. Such as I think you use a tub or container that holds a certain amount of volume. You use say 3 drops. Now I have the same volume but smaller individual molds that I got from gadget. Am I making sense. I know if I make a big cup of PR it gets hot and cures fast if I take the same mix and spread it out in a thinner container it will not cure the same. Is that making any since.

I would like to give PR another chance it does cost less.

Your thoughts
Click to expand...
 
Thanks Bruce for adding your findings. I hoped you would chime in because you explained it much better than I could have.

I too have used the CA and it works fine for me. Try painting on a layer of raw resin...it is quicker and easier to do than using CA.

Do a good turn daily!
Don
Originally posted by BRobbins629

A little while back I took a look at very thin slices under the microscope of a snake skin cast very similar to your failure. What I saw was irregular shaped voids, not the spherical type you would get from dissolved gas coming out of solution, but ones that could be generated by the resin not wetting the surface of the skin. I think that what was happening was that portions of the skin had high amount of glycerine which didn't allow the resin to bond to the skin surface and as it cured, the surface tension pulled it away or there was some shrinkage and again because it wasn't bonded to the skin, a void appeared. The off color comes from light refracting in this irregular void.

Alot of good ideas are above to minimize this effect. Don's method of soaking in uncatalyzed PR allows the surface to equilibrate. Although it takes me a little longer, after gluing to the tube I paint the entire surface of the skin with thin CA using a nail for a paintbrush until the entire surface is hard. I don't have nearly as many under my belt as some of these folks, but so far so good.
Click to expand...
 
Don - One thought about the relative thickness of different PR resins. When we say we are using PR resin, while it is theoretically more than 50% polyester, it also contains a material called styrene momomer. Styrene monomer, the starting material for polystyrene, is used in PR resin as a thinner. It is also what makes the stuff stink. MrFiberglass even lists styrene on his site as a thinner for PR resin and you can buy it seperately so I suspect that while the weather may play a role, the 2 resins may have different concentrations of styrene.

As for painting with PR, when I first started casting, my wife said no more in the house so that's why my shop in now a nice little out building in my back yard. I still do some work inside the house such as mounting skins on tubes, but all the noisy and smelly tasks are done in the shop. A little CA is okay, but I wouldn't last long if I brought PR back in the house.
 
Curtis - agree that there are some health hazards with styrene, but there are billions of pounds used around the world and if handled according to directions there is very minimal threat. Just because something has a bad odor does not mean it is it highly toxic and vice versa - look at carbon monoxide, a colorless, odorless gas.

Here's from the MSDS for part A of Alumilite - pretty scary?


2007113031825_Alumilite%20part%20A.jpg
 
Bruce,

I did not say anything at all about Alumilite. I did not even say that Alumilite was better than PR in my discussion of Styrene. What does the MSDS for Alumilite have to do with this discussion??

If you must, here is an excerpt from a Styrene Monomer MSDS:

Toxicology
Toxic. Carcinogen. Mutagen. Corrosive, causes burns to skin and eyes. Lachrymator. Harmful by inhalation, ingestion and through skin absorption. Long term exposure may affect CNS.

Personal protection
Safety glasses and gloves. Effective ventilation. Handle as a carcinogen.
 
Just to provide some more information, this is from the MSDS for Silmar 41, the PR casting resin many use. The data from indutrial exposure where workers are exposed so significantly higher concentrations of styrene than us pen makers gives me comfort.

"Styrene has been identified as a possible human carcinogen by the International
Agency for Research on Cancer (IARC). The IARC determination is
based on "limited evidence" in animals and other "relevant data." IARC
concedes there is "inadequate evidence" on humans for its findings.

The Styrene Information and Research Center (SIRC) recently sponsored studies
to evaluate potential health effects in laboratory rats and mice exposed by
inhalation to styrene for six hours per day for five days per week of their
lifetime. The rat study, completed in 1996, showed no increased incidence of
tumors related to styrene exposure at levels up to 1000 parts per million
(ppm). The results of the mouse study are in the process of being analyzed,
and so far only the lungs have been evaluated. The number of lung tumors
observed at exposure levels of 20 to 160 ppm was increased as compared to
the number of tumors seen in unexposed mice. These lung tumor results from
the mouse study have been added to the MSDS for styrene.

The lung effects in the new mouse study are in contrast to findings in other
studies in both rodents and humans, including the recent SIRC-sponsored study
in rats. No link between styrene exposure and an increased incidence of
cancer has been found collectively in eight studies of workers in the
reinforced plastics and composites industries prior to 1992, or in two
subsequent studies of composites/reinforced plastics workers. All together,
over 90,000 people have been studied. Exposure levels in these industries are
above the levels routinely measured in styrene and polystyrene production.

Also in the recent animal studies, irritation and degenerative effects on the
olfactory cells in the nose (responsible for the sense of smell) were observed
in mice exposed repeatedly by inhalation to 20 ppm and above, and in rats
exposed to 50 ppm and above. Atrophy (degeneration) of the olfactory nerve
was observed at levels at or above 40 ppm in mice and at or above 500 ppm in
rats. SIRC is conducting follow-up research to further understand these
findings and their possible importance to humans. Liver damage has been
reported in mice at exposure levels of 100 ppm or above; comparable liver
damage has not been reported in rats or humans exposed to styrene. It appears
that mice are more sensitive to styrene than are other species. Information
about potential damage to olfactory cells, irritation in the respiratory
tract, and potential liver damage has been added to the MSDS for styrene.

We recommend that the precautions in this MSDS be followed."
 
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