Epoxy resin

Epoxy advice....Is it possible to add pigment or dye to stock, unmixed resin, so than when it is combined with hardener you have a good visual key as to the quality of combined mix. I notice that many pre-blended epoxy fillers have a distinct colour difference between part A and part B to promote thorough mixing

 

Yes and no. Depends of the chemical characteristics of the pigment allthough most of them are quite stabile, so I'm afraid you just got to test and try.

 

Powdered pigments can be added to the resin with good results and no affect on the peel strength or general physical properties of the cured goo.

Most paint supply stores have powered pigments and there are two types, water based and those intended for oils. Both will work. The powder is held in "suspension" in the matrix (if it doesn't turn liqiud) and has little effect on the performance of the epoxy. I've been using powders for several years, including soap stone and children's colored chalk, both of which make wonderful pigments, once ground very fine. I've also used food coloring and fabric dye (both powdered and liquid).

The best thing I've used is powdered tempera (water based craft paint powder). I know of restorers who use enamel paint to color epoxy.

Log onto WWW.WestSystem.com and type pigments in the search box. This will provide you with some basic testing data on different pigmenting products.

 

I have used a product, called Polycolour, supplied by Solid Solutions in AUS that is recommended as an epoxy dye. It is described on the label as containing silicon elastomer.

With black dye you only need a few drops per litre to turn the whole mix black. I add this with the catalyst and then stir until the black dye is completely distributed. I have found that the mixing is very easy to achieve apart from a thin layer on the bottom of the container. So make sure your stirrer covers the entire base of the container and you should have a well-mixed batch.

I have not noticed any reduced performance with the epoxy but I have not done quantitative testing.

Rick W.

 

Thanks Par. I'm familiar with pigment that can be added to the epoxy after it has been combined. I would like to add a few drops of say BLACK to the catalyst and a few drops of perhaps White to the resin... before mixing.... to give a valuable visual key to the quality of the mixed batch. In the way in which Rick describes. Thanks Rick, Ill do some research on the internet concerning this dye Polycolour, by Solid Solutions

 

This is interesting.
So I could colour up some epoxy filler that is normally a glassy opaque kind of stuff.
With a white pigment I would be able to maybe make good some damage without painting afterwards. like repairing a chip in the gell coat?

 

Frosty,

Yes, but the colour tone matching can be problematical.

There are shades and shades of white.

Pericles

 

All epoxy, regardless of filler material or pigment added will break down from UV exposure. The surface will still require some sort of coating, which could be clear if you have a good match or painted if not.

 

Yeah thats true, but a chip in the gellcoat shows up as black --A slight colour difference would be much much better. The eye might not get attracted to it. Im talking --say 3 square mm chips. You know on corners where the fibre glass didnt reach or bond to the gell coat and then it cracks open a hole. Got some in the bathroom.

Would white nail varnish do? something like that although I never seen this available,--(gell coat repair in a nail varnish bottle.)??

Ive seen stove enamel in a small bottle for fixing chips on cookers --would that do?

Sorry Bulkhead Im not hijacking

 

I suspect you could fill little dings with enamel (finger nail goo is enamel paint). I would imagine it would take several coatings to bring it up over level, where it could be buffed down to level and perfectly smooth (if you cared to do this effort). Other wise yes, the automotive touch up paint in a stick or bottle applicator may be just the ticket for this type of cosmetic touch up.

 

I started using chaulk line powdered chaulk this last year. It is very cheap. Comes in squeeze bottles so it is easy to dose. Works very well when there is a bit of silica in the mix. Comes in florescent green, orange, red, yellow, blues. Will give a pastel to rich color depending on dose. Mixes slightly faster than tempera paints.

When mixing in fillers this works to see that the mix is complete. If not there are pigment streaks and color inconsistency.

I use this technique for bog in coner fillets and in fairing bog. The results of the fairing can be seen here.
http://www.boatdesign.net/forums/showthread.php?t=20209

Also for holding the waterline reference, I colored the bottom fairing bog with brown tempera. That was the pigment I was using before finding chaulk.

The red cast to the hull laying in the forms is the fill coat for the fiberglass weave. It is red in color, so that I will not sand into it.

 

to fix chips in the gelcoat , get some brushing gel so its a little thick place a little into the chip enough to fill it you may want a little more as it tends to srink, then place a peice of tape clear scotch-tape not masking tape, when its cured pull off the tape and you will have a level repair thats glass smooth, with a little time and pratice you will be able to do this with out having to sand it level, if you do have to level the repar yuse a razor blade held perpendicular and shave the gel down flush with the rest of the boat then cut and polish, you can do the same with epoxy, and if you have the gel color matched the repair will blend in