Not sure exactly where to put this. please move if needed.
So I’m going to be going from a drop in aluminum tub for my rear storage to a fiberglass/gelcoat part. I think I’ve gotten the process down for making the mold and everything. My question is what type/size of glass mat would you guys recommend? The tub will be about 26”x21”x15” and will need to hold maybe 20# worth of gear in it at any given time. It will need a flange around the top to locate itself in the hatch that will need to handle the weight as well. I appreciate any insight you guys can give me. I hate to make it unnecessarily heavy, but certainly don’t want it to break.
1 Like
For that I’d likely do something like this:
Gelcoat
3/4oz csm skin coat let cure and cool then hand scuff with 36 or 50 grit
1@ 3/4oz csm, 1@ 12oz biaxial wet on wet or 1 1208 biaxial mat side towards mold
1 4mm core mat such as soric on the bottom plus another 1208 over that. Could go lighter yet but this should produce a good strong part. You can drop down to 10oz cloth no problems here and maybe even 7oz just depends how strong you want but this should give you a good starting point to play with.
I’m not an expert, but I’ve been using 1 1/2 oz chopped strand mat and 1708 with polyester resin. The 1 1/2 oz CSM isn’t very thick or strong but give a good base, 1708 builds thickness and strength. Below are before and after of my console built with just those three items. It’s pretty strong.
Check out fishbumptv on youtube.
1 Like
I’d follow @JCDesigns recommendation. Like you, this is what he does for a living.
1 Like
I would make your first part out of simply 3 layers (or more) of 1.5oz mat to equal 3/16”+ and beef up the lip a little thicker. If you want it stronger/lighter then you can get more creative on subsequent parts, but sometimes just regular ol chop/mat works fine. Worst case scenario save the tub for a plug or use at the shop for storage.
My family has been making fiberglass trash cans and tubs for 65 years this way (but we use a chopper gun). Obviously we dont have the weight requirements of a skiff hull though!
