If you need to do some fiberglassing with cloth and epoxy resin, this Instructable can save you some mess and grief. Manufacturers of fiberglass and epoxy materials offer booklets that can provide you with instructions for success. However, through my own experience I have developed helpful tools and tricks you won’t find in the books.
The photo is of solid 14-foot boat hull on the right and its twin on the left that I fiberglassed and painted, one my several projects that taught me these lessons.

step 1 Specialized tools
The yellow plastic spreaders are recommended for pushing the epoxy into the fiberglass cloth, however they are hard to grip when your gloved hands are wet with epoxy. I used two screws and nuts to attach the plastic handle of a defunct disposable foam paintbrush to each spreader. I prefer the rubber spreader for big jobs and added a handle made from a length of broomhandle that I slotted, and two strips of sheetmetal to add side-to-side stiffness. Both kinds of spreaders are available where epoxy products are sold and by mail order.
The shape of the scissors enable them to easily cut fabric that is flat on a table, and they have a palm bar rather than the usual cumbersome thumbhole. The scissors have a spring-open feature, are Fiskars item 9911, Wal-Mart, $14.
I use waterless handcleaner, such as Goop brand, and a stiff brush to clean these tools before the epoxy can set, and after many uses those in the photo are still clean and not sticky.

step 2 Mix small epoxy batches
I found a way to mix small batches of epoxy resin and its hardener, in proper proportions, even if the liquids are in large containers. A little effort in advance will make the job easier. Mixing epoxy in graduated containers is costly, and measuring the liquids in a graduated container then pouring together into a small mixing cup can lead to inexact proportions. First, get sleeves of a few sizes of clear or translucent plastic or paper cups (not waxed!) that will hold the different amounts of mixed material you think you might need, with enough room free at the top of the cup to allow for stirring. Using the following notes, make a reusable “calibration half-cup” for each size cup and for each size batch within that cup size.
Note the half-cup has its upper rim cut off so it will nest perfectly onto the side of a new cup. It is marked “2R:1H,” to denote that this half-cup is to be used with epoxies that call for a ratio of “2 parts Resin to 1 part Hardener.”

step 3 Make and calibrate the half-cup
Photo shows how “calibrated half-cup” is put onto the side of a cup that will be used for mixing a small batch, and the calibration marks transferred to the new cup.
For each cup size, take a new cup and put WATER into it that is about one-third the amount of the final batch of mixed epoxy, and make a mark at that level on the outside of the cup. Pour all that water into a clean cup and mark its level on the outside and label that mark as “H” for hardener. Put water into the first cup again, to its marked level, pour that water into the second cup on top of the water already in it, then repeat. Mark the top of the water level on the outside of the second cup and label it “R+H” for resin plus hardener.
Repeat the procedure if you want to calibrate the second cup for a larger epoxy batch in that same cup size, putting the level marks on the opposite size of the cup. Cut the calibration cup in half vertically, and keep it with your stash of that size cup.

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