Fiberglassing Tools and Tricks
Intro: Fiberglassing Tools and Tricks
If you need to do some fiberglassing with cloth and epoxy resin, this Instructable can save you some mess and grief. Manufacturers of fiberglassing 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. Intro 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 glass 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.
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."
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.
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.
STEP 4: Small Batch Cup Ready to Use
Small mix cup has calibration marks (fattened to aid in photography) transferred to it from the calibration half-cup, and the marks will be visible through the translucent sides of the cup. Viewing into the cup, carefully pour hardener into the cup to the first line, then carefully pour resin up to the top mark, and you will have exact mix ratio. Mix and use from that one cup, then discard it.
STEP 5: Foam Clamps
Vaccuum bagging is great for clamping fiberglass tightly over a shape and removing air bubbles, but it is too complicated and costly a procedure for occasional use. For smashing wetted cloth tight to the sharp bow of a hull, I made clamps by backing up foot-square blocks of 4-inch thick foam rubber with squares of 3/8-inch thick plywood and wooden sticks. Before use, I wrap plastic wrap around each foam clamp and tape it to the wood backside. Two slide clamps squeeze the cloth and conform it to the hull mold's shape. Rubber foam can be cleanly cut using straight edge guides and a hotwire cutter. Click on link to see album "Cutting Rigid Plastic Foam," click on "READ FIRST" instructions for reading and printing fine text. http://www.flickr.com/photos/sm_vermn/tags/foamcutter
STEP 6: Squeeze When You Can't Vaccuum Bag
Wet fiberglass cloth can be made to wrap over a sharp edge, but it will lift up off the edge before the epoxy sets unless it is clamped in place. Here is the full-body version of the foam block clamp. I used a sheet of white upholstery foam, 1-inch thick, to press the wet cloth around the bottom of the hull (facing up in this photo). I pre-cut strips of a stretchy 5-inch wide colored foam, sold in rolls at home centers as a barrier between the top of a house's foundation and the house itself, marked each strip in sequence. Once the fiberglass was wetted out, I smoothed a precut strip of thin clear plastic tarp over the wet fabric as a mold release, placed the white foam sheet over that, then stretched each strip of the colored foam and taped its ends together with duct tape.
STEP 7: The Mummy Unwrapped
The hull after the foam has been unwrapped. The fiberglass conforms so well to the shape, even where it is folded double across the front edge of the bow, that it is virtually invisible.
STEP 8: Deck Gets Fiberglassed
Once cloth is wetted onto the deck and the edges trimmed, thin plastic sheet is smoothed over it, pulled down and taped to keep the cloth wrapped over the sharp edge of the deck until the epoxy sets.
These hints come from an article I had published in the 01 Aug 1998 issue of MESSING ABOUT IN BOATS magazine. It contains other information that does not fit the step-by-step format of Instructables. Click link to an album that contains the article, click "READ FIRST" instructions for reading and printing fine text. http://www.flickr.com/photos/sm_vermn/tags/toolsntricks
To see my related projects, enter unclesam into the home page search box, scroll and advance pages to view them all.
U.S
These hints come from an article I had published in the 01 Aug 1998 issue of MESSING ABOUT IN BOATS magazine. It contains other information that does not fit the step-by-step format of Instructables. Click link to an album that contains the article, click "READ FIRST" instructions for reading and printing fine text. http://www.flickr.com/photos/sm_vermn/tags/toolsntricks
To see my related projects, enter unclesam into the home page search box, scroll and advance pages to view them all.
U.S
37 Comments
BuksV 8 years ago
Ordinary washing machine powder and water works the best for resin cleanup
Ben DangerH 7 years ago
thanx
AlexH35 8 years ago
Low cost weigh scales are the best for accurate proportions of epoxy as the specific gravities of the two components are very close. Using a .1g accurate scale (max 1kg) for small amounts of 4/1 epoxy and I can reliably make 5 grams of epoxy. I have another set of scales that does 5kg max. The 1gram scales cost $ 15 and the 5gk $ 25. Well worth the investment for easy and accurate mixing.
Ben DangerH 7 years ago
thank you for the tips :)
thordruid 10 years ago
Hello, we are a small bicycle company, not for profit organisation. for the 20 years jubilee critical mass ride in London, we would like to make a sound system trailor from fiber glass, using a roof top box of a car as a base. We would like to make a miniatur version of the AN 79 or AN 225 aircraft. Could you be so kind to assist us with tips and tricks and how we should go about?? we have never done this job before and we have a 3 weeks to work on the project to completion.
trebuchet03 16 years ago
Poppy_Ann 15 years ago
pfred2 11 years ago
Ellen the Generous 11 years ago
With that said, I have an actual question: When you get to this clamping stage, how do you get the downward pressure to pull the cloth over the tip of the hull? Obviously the foam clamp provides significant side to side pressure, but is it that the foam can compress and 'hug' the form so tightly that it provides uniform pressure in all directions?
unclesam 11 years ago
Hope this answers your question, Uncle Sam
fireheadfirehead 15 years ago
unclesam 15 years ago
pinkishfloydus 15 years ago
LynxSys 11 years ago
There's a lot of information floating around on how to do kayaks. The easiest thing to do would be "stitch and glue" construction using sheets of plywood that you sheathe in fiberglass. If you want to produce a boat with compound curves, you're looking at wood-strip construction (often called cedar strip), which is also sheathed in fiberglass inside and out, creating a very strong "sandwich core" material. I'm getting ready to build a cedar-strip sea-kayak of my own design, and so I've done a lot of research on these methods recently. I also have a few years of experience repairing commercially produced kayaks, so drop me a message with any questions that Google can't answer. I hope this gets you off to a good start!
junkerjp 11 years ago
adam.bonahmcarter 13 years ago
Another good way to measure quantities is to mark the levels on a stirring stick. As long as the same type of cup is used the stick can be used every time to measure and then stir. A scrape off of any extra mix on the side of the cup, wipe with paper towel and then good to be used again.
JesusFreke 13 years ago
I don't recall the scale I had bought offhand, but it was a 500g scale with .01g precision for around $60 (or was it $40? I don't remember). You could find a .1g scale for quite a bit less - probably around $20, and would likely work just fine. The .01g precision is nice to have though, I would recommend it if you can afford it.
Agavedidgerbrad 13 years ago
rimar2000 14 years ago
dk-info 14 years ago