Fuel Tank Hatch repair
 

got my fuel tank hatch off , old wood removed and all sanded/grinded and ready to epoxy the new wood down...I have some filler to thicken the epoxy resin as was suggested on some of the posts here to make sure any voids are filled. What kind of viscosity am I looking for when adding the filler? still fluid enough to roll on or more of a pasty trowel on type of consistency? this is my first ever work with resins so its all new to me. I havent read the mfg literature yet to see if there is a max allowable before comprimising the strength of the stuff but thought I would ask here.

Visc.
 

Anywhere between mayonaise and peanut butter. But closer to mayo.

go to classicseacraft.com , forum then to repairs and look in the first one titled "here we go again" look how he did his hatches that's the best explanation i've seen so far.

Because my hatches were very thin after removing the rot and grinding
I used 2 layers of 1.5oz mat wet out real good with polyester resin then placed composite down and weighted the dry side down with builders blocks, batteries and such. Drilled holes in the composite about every 4" beforehand to allow air to escape. Let it kick, sanded the resin around the edges and that which poked up thru the holes and glassed the backside. Gorilla strong.
I am not fluent with epoxy. So don't use my comment as "the word" but
If you are using epoxy with thickening agents, I would think you would still want it thin enough to put on with a roller and let it flow out flat. If it is thick enough to trowel on you would have more hills and valleys creating voids causing you to put more force on the wood coring to get the air out. If on the other hand you were doing a vertical transom and were using transom clamps I would say go ahead and make it thick, trowel it on, clamp the coring down good and tight until the paste is oozing out from behind the coring and wipe off the excess to save time later.
Someone will chime in and rip me a new one but this is my logic for what its worth.
See BenFishin already did. Mayo or Miracle Whip? My thinking was that air bubbles move more easily thru unthickened epoxy than mayo or peanut butter:zip:

I will personally recommend a flow consistency like honey, you are basically looking for penetration and filling voids on a flat surface with a backing skin, Mayo will be better for a vertical fill or a lay up that dictates a thicker flow.
If you are using Epoxy be sure to use the correct thicken agent.
I personally did not use a thickening agent with my poly resin when I did mine, I wanted the flow and fill to be 100 % this just my 2 cents . Ridge is correct be sure to drill those holes..

thanks for everyones input.... I guess I settled on a Honey mustard consistancy :fam:. Just thickenied it up a little....still flowed pretty good I guess.....drilling the holes in the composite was the first time I'd seen that so I drilled some 1/4" or so holes every 6" or so.....actually had a fair amount of resin squeeze up through the holes which i had to grind off this morning....

just put the glass and resin on the outside....definitely glad it wont be a visible surface as I'm sure it wont be perfect but it will be fine.... I guess what I gathered from all the different ways people have done this is that at least for this kind of repair its a pretty forgiving procedure....slap the crap on there , clamp it...done. the resin does all the work. Glad some of the mystique is gone from fiberglassing now that I have my first project under my belt....

BTW ...bailed on replacing the fuel tank.....the foam around that tank is bone dry and all looks good...I can just hear myself this season "ever since I replaced that tank i've had this problem and that problem"....if it aint broke dont fix it and at this point I'm not looking for more work. someday when it goes I'll be ready to do it. but for now the hell with it.

sounds like you nailed it!!!!

good call on the gas tank ... i hope i am as lucky :)

Excellent. Nothing like jumping right in and gettin it done.. If the holes had epoxy running up thru, you got it right without a doubt. :clap::beer: Good job.

Sounds good, been needing to do mine for the last 7 or 8 years.

Now I see why you have no fear of "Swiss Cheese"... :clap:

Hey Rob...gotta pull the tank hatch on the 21...the lid itself feels solid, but need to see what's goin' on under there...any words of wisdom on gettin that puppy off?...