Minimum Thickness for Silmar 41

Signed-In Members Don't See This Ad

builtbybill

Member
Joined
Dec 17, 2014
Messages
239
Location
Clayton, NC
Hello,

I have a quick question for some of you that are more familiar with Silmar 41. I just bought a gallon, so that I could cast some blanks, but I also have a table top that I would like to pour this on. My question is what is the minimum thickness that I can pour Silmar 41, and I do have the surfacing wax to add to it? I would like to be able to pour it at about 1/4 inch thick, and temperature-wise it is greater than 90 degrees where I am at, in case that makes a difference.

Thanks,

Bill
 
Signed-In Members Don't See This Ad

Ed McDonnell

Member
Joined
Oct 20, 2008
Messages
2,291
Location
Melbourne, FL
I don't think Silmar 41 (or any PR) is a good choice for this application. I think you would get better results with an epoxy resin. But, if you decide to try there are going to be a couple challenges you will have to overcome. Silmar 41 shrinks as it cures and there will be a risk that it will either warp your table top or delaminate itself from the table top during the cure. Even if it doesn't warp or delaminate, the top surface of the resin pour will be unlikely to cure flat / perfectly level and will end up heavily textured. This will require a lot of work on your part to get a flat polished surface.

Adding wax to the resin is fine if you are sure you don't want to do any subsequent pours, but rubbing on a paste wax before final finishing will do the same thing and get rid of any tackiness and make the surface easier to sand (once it fully hardens). Keeping oxygen away from the resin while it finishes curing it what prevents the surface tackiness you sometimes get with freshly cured PR.

Building a mold that would effectively sandwich the poured silmar 41 between the table top and a rigid non stick barrier (acetal sheet on a stiff backing could work) for a week or so while it fully cures and could solve a lot of the problems, but it would be cheaper and a whole lot easier to just use self leveling table top epoxy resin for a one off project. You might also consider encapsulating the table top rather than top coating it. This might mitigate some of the shrinkage / delamination (during cure) issues.

Silmar 41 is not an adhesive and it may not satisfactorily bond to the table (which is a separate, but related issue to shrinkage delamination). You might eventually notice shiny areas where it starts delaminating at any point in the future.

I pour layers that are 0.010" thick, so 1/4 inch would not be too thin to cure. It might or might not strong enough to withstand your ultimate use. Additionally, if the table top will be in a cold environment it will be more at risk of chipping and cracking from impacts.

FWIW.

Ed
 

jttheclockman

Member
Joined
Feb 22, 2005
Messages
12,659
Location
NJ, USA.
I agree with the statement you want an epoxy resin. It will adhere better. You have been warned. good luck.
 

builtbybill

Member
Joined
Dec 17, 2014
Messages
239
Location
Clayton, NC
Thanks for all of the advice. I just want to clarify one thing, just in case it makes a difference, the resin will be getting poured over a 9"x60" concrete shelf, that has been roughed up with a needle gun, so there is a lot of surface texture. This shelf has starfish, sand dollars and chambered nautilus fossils embedded in the surface, and will be going ext to an antique clawfoot bathtub. Does anyone have recommendations for a fairly inexpensive clear epoxy that can be tinted to a translucent blue?

@Ed McDonnell that was a great write up, thanks!

@djrljr a have watched a lot of their videos, absolutely incredible what they do, I just can't afford their products right now. The VA screwed up my pay and has been withholding $650 a month since February and until this gets fixed I am on a pretty tight budget.

Thanks again,

Bill
 

jttheclockman

Member
Joined
Feb 22, 2005
Messages
12,659
Location
NJ, USA.
Expense is a relative term. Not sure how much is needed and I am sure there are formulas for this but you went to all the trouble to get the project to where it is and now you want to cheapen out for a few $$ You can look at bar top epoxies. The same people that make Silmar 41 make top coating marine epoxies. http://www.uscomposites.com/ Good luck post a photo when done.
 
Top Bottom