CA finish (again for the 49th time it seems)

[Jeff Leslie]

I have just gone back to class and started turning pens. A long way back from turning boxes and platters, but a large and steep finishing / learning curve in any case.

Having done some work already with CA, I was more than interested in seeing how the glue would come up as a finsih against poly and nitroceluose.

I practiced with CA hard on a variety of Oz timbers, incliuding beefwood, fiddleback redgum and blackwood. The results, as expected, were great.

But all that testing was done without bushes! (And yes, I have ordered the right ones now!)

At this early stage, it seems to me that, as with all finishes ""ënding"" on a point, the main problems with CA and any hard finish are:

- clean breakage on the join after curing (with or without sealing the bushes)
- sanding though the finish back to bare wood at any stage
- deciding on whether to use thin or medium CA
- estimating the % of build up of finish over the bushes prior to them being sanded down
- production runs where poly or spraying might be a better option

We are no doubt fortunate here in Oz with such a wider variety of timbers to use - and many of them hard and colourful. But I am still not sure whether to get the NC spray out and avoid the CA route altogether. Problems dealing with spraying a volume of barrels is a given. Same amount of fumes, but different.

Ideally, I want a finish that I can complete either in batches or separately, but it must be worthwhile. A hard wearing floor finish applied to blanks on a modified and extended mandrel seems a good alternative at this point. Ideas and thoughts welcome.

CA remains an essential part of my turning journey, particularly on burl and highly figured pieces. So don't dismiss my liking of the merits of CA.

I want to hear from mass / production pen turners that have done the sums - as well as those that have not. Learning from all sources is the key. I have seen countless clips of CA finishes but none where the alternatives were an option. Give me your thoughts, particularly if you spray as a matter of course.

 

[leehljp]

At this early stage, it seems to me that, as with all finishes ""ënding"" on a point, the main problems with CA and any hard finish are:

- clean breakage on the join after curing (with or without sealing the bushes)
- sanding though the finish back to bare wood at any stage
- deciding on whether to use thin or medium CA
- estimating the % of build up of finish over the bushes prior to them being sanded down
- production runs where poly or spraying might be a better option


Ideally, I want a finish that I can complete either in batches or separately, but it must be worthwhile.

Clean Breakage problems drove me to using "TBC" or Turning between centers. In TBC, the bushings and single blank are put between the live center of the tail stock and a dead (drive) center in the head stock. After getting the blank round, the bushings are taken off and the blank put back between the centers. Finish turning to size, size is determined by using calipers. Sand, finish. Finish at this point does not have a smooth CA covering on the bushing because they are not there, so No Breakage.

% of build up - I usually sand down to about .005 below the size I want and build back up to about .007/.008 larger and then sand that down to about .001. This gives one a perfect fit and finish between the blank and hardware.

Batches: some people do that. On occasion, I have used lacquer but the lacquer that I used in Japan took 24 hours to cure sufffeciently for me to finish. I developed a method (from others on this forum) of "dipping". I would turn and sand about 10 to 12 blanks to size, put corks in both ends with an eyelet/hook screwed into the cork; Dip each one in lacquer and hang each one; after dipping all, wait a few minutes and dip each one again and hang overnight or for 24 hours. It would take me 5 to 6 hours at best to turn and finish 10 blanks, so doing a batch of 12 dipping would work out similar.

As to Thin or medium CA, it depends on my mood and thoughts at the moment. I did discover this past year that I could build up more coats of thin (i.e. an overall thick layer of cured CA) faster that I could with medium, as medium takes a few minutes to "cure" after two or three layers. I can get a thin layer to cure in seconds and several thin layers to cure in several seconds. I use hard foam or rubber gloves to apply CA rather than Paper Towel as PT absorbs too much (75% or so) of the CA for me.

I am not sure this is what you were asking about but these are things that I have tried and my experiences.

 

[todddarling1]

Foam Question

When you say hard foam, not styrofoam right? Something like the Foam craft sheets?

Been having a devil of a time with medium CA, I'm good with the thin on papertowel but medium is another story.

We just started using CA Love the finish.

Todd

 

[Randy Simmons]

In order to prevent CA buildup on the bushings, I pull them out of the tube a bit while I let the finish dry.

The way I do my finish, the thickness is about +.1 mm Which is thin enough that to me, and my customers, it really doesn't matter.

I can't speak to the quality of pen finishes other than CA. I DO know that most waxes and oils won't take, because the wood is way too thin.

I would certainly recommend medium. I do a base coat of thin to stabilize the wood, and then two (maybe three) coats of medium, and then a top coat of thin. Most guys here it seems spend forever putting 20 coats of thin on. I hate that. I use the plastic bags from the components sets to cover a finger and spread it on that way. I don't use accelerator, you can, doesn't really matter. That stuff is going to hold up to your sanding a lot better than thin, and you probably won't sand through it.

My three cents

Randy

 

[leehljp]

When you say hard foam, not styrofoam right? Something like the Foam craft sheets?

Been having a devil of a time with medium CA, I'm good with the thin on papertowel but medium is another story.

We just started using CA Love the finish.

Todd

Yes, foam craft sheets. I used the wrong term but I didn't want for the idea of foam "brushes" to be perceved. Some would. :redface:

 

[todddarling1]

Cool thanks. that what I thought but wanted to make sure.

When you say hard foam, not styrofoam right? Something like the Foam craft sheets?

Been having a devil of a time with medium CA, I'm good with the thin on papertowel but medium is another story.

We just started using CA Love the finish.

Todd

Yes, foam craft sheets. I used the wrong term but I didn't want for the idea of foam "brushes" to be perceved. Some would. :redface: