Epoxy seal coat after staining???

So when applying an unthickened epoxy seal coat after staining does that get sanded prior to glassing. I'd be doing it to lock the stain in place with just a quick roll on vs the activity of filling the weave when glassing moving the stain around???
Thanks for any suggestions, PP

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RE: Epoxy seal coat after staining???

Assuming you're using an alcohol- or water-based stain before epoxy I'd trust that seal coat has to be heavy enough actually to seal the ply it's applied to.

Subsequent layers could be compromised if a light roller-coating leaves areas of uneven or inconsistent coverage, leaving you with an unevenly bonded foundation.

And yes I'd want to sand that first epoxy once it's set & cured so any bubbles, proud wood fibers or other irregularities are removed, the better to accept the 'glass w/o issues.


RE: Epoxy seal coat after staining???

   So I did the seal coat and the color stood up well but after sanding some low shiny spots remained. Will these show through after glassing. Couldn't really sand them out without risking sanding down to the stained wood???

RE: Epoxy seal coat after staining???

Get yourself some brown 'ScotchBrite' pads put out by Norton Abrasives. Use that, maybe dampened w/water, to abrade those low, glossy areas before applying more epoxy. We sell it at the TrueValue hardware store where I work in packs of 5 sheets so look around... maybe you'll find some rather than buying on-line.

That stuff's super for 'de-glazing' epoxy prior to recoating where sanding would be difficult or better avoided entirely. Follows contours better than paper too, sometimes a plus.

RE: Epoxy seal coat after staining???

fwiw, i routinely will apply a seal coat after staining to hold the stain in place.

the  seal coat is the least amount of epoxy i can apply to basically seal the pores of the wood/hold the stain in place.   when i do it, it rarely is shiny....very little epoxy is applied in a seal coat.

i don't sand after a seal coat and just go right to glassing.   there is really no bonding issue becuase the seal coat should not be o thick to creat a smooth/shiny surface. 

fwiw,  i would have made sure the wood was smooth/sanded before sealing and the stain/seal coat is not going to change that.  if i ended up sanding, i would likely effect the color becuase the stain does not go far into the wood at all....which sounds like what you did.   fix it with stain first, befre glassing,  becuase what you see is what you will get.

i would not introduce water at all into the equation.  denatured alcohol can be used to thin out stain.

i realize what i am saying appears contradictory to spclark.  there is a lot of different approaches people have taken.  i routinely work with stains on my kayaks and my recommendations are based on that experience.

good luck


RE: Epoxy seal coat after staining???

No issues with hspira's recommendations. He's done more with stained substrates subsequently seal-coated with epoxy that I can lay claim to.

Still, from what poopdeckpappy says about glossy spots leaves me thinking his seal coating technique isn't as practiced as hspira's, hence the glossy spots he asked about.

Were I faced with similar I'd dull those glossy spots as I suggested so a mechanical bond to subsequent epoxy coats would happen. Best practice may be to have a builder apply another application of epoxy once the initial thin seal coat has begun to cure? This adds weight of course, which may not be desired.

Sanding a seal coat is a tricky operation. If it’s also an uneven coating, it’s easily broken thru in the thinnest spots while thicker areas, where glossy spots appear, aren't as fragile.

The OP doesn’t mention what brand of epoxy he’s using. My experience with denatured alcohol used for smoothing fillets suggests there are elements of MAS LV epoxy mix that are soluble in alcohol; I’ve observed deposits resembling water stains where excess alcohol has collected then dried after these operations.

Alcohols are inherently alkaline, in that they universally contain an -OH hydroxyl group. So it's not unreasonable to expect stains applied in an alcohol solution may be disturbed by a direct application of epoxy blended with a hardener having an alkaline nature. This may be why stains tend to migrate when heavy applications of epoxy are applied such as when fiberglass cloth is saturated with epoxy on a stained, unsealed substrate, leading to what the OP mentions about “…the activity of filling the weave when glassing moving the stain around???”


RE: Epoxy seal coat after staining???


I am not an expert, but to me it doesn't seem like applying fiberglass with epoxy is much different than applying a sealing coat of epoxy over the stain.  If the sealing coat does not mess with the stain I don't see why applying fiberglass with epoxy would bother the stain? Am I missing something here?


RE: Epoxy seal coat after staining???

hi jack,

you're not missing anything.  the conversation just has has to be put into context with techniques and the boat cosmetic design/goal of locking in the stain and how you approach assembly of the kayak.

first, seal coats to 'lock a stain in' are only important if there is somewhere that you want the stain and somewhere where you don't want the stain.  so if everything is getting stained the same, you can just stain and move onto glassing.

when i do a seal coat of epoxy to lock stain in, i am masking off any area i don't want to have stained or working on pieces that i want stained that i don't want to bleed into another part of the assembly when they eventually are brought together..

fwiw, when i do seal coats and masking is involved,    i work very quickly to minimize the 'lifting and moving of the stain' that occurs once wet epoxy is introduced into the equation.   this is important becuase masking tape won't hold up well to a very wet epoxy application...it will bleed under the tape if it is too wet.

once the seal coat sets/cures, the stain is locked in where the stain is and will no longer move once additional epoxy (for glassing for example) is applied.

i hope that helps answer your question.



RE: Epoxy seal coat after staining???

I use much the same technique as hspira.  In addition to preventing the stain from bleeding over to non-stained areas, I see two other benefits to the seal coat.  First, using a roller to apply the seal coat does a great job of evening out the color and elminating and splotches that you made wile staining.  Secondly, it provides a bit protection for the stained wood during the construction process.  

RE: Epoxy seal coat after staining???

   @ Mark N. Thanks for your input. Please see my other post about varnish turning stain brownish. Is that Mohawk Oxblood you used? What varnish on top?

@ spclark, hspira. Thanks for the replies . I think just my inexperience caused me to put the seal coat on a little heavy. I have glassed and the color looks fine. Yet to finish filling the weave  but more concerned about the final finish with varnish. See above.

BTW I'm using Mohawk recommendation by CLC thinned with DA to reduce color.

This is the deck we're talking and the hull will be painted.

Thanks again guys. PP

RE: Epoxy seal coat after staining???

   Started out red but then this after glassing and five coats of epiphanes clear varnish

applied as per directions on can


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