It has been a while since I could muster an instruction together. With a few big projects in the works (and a curious 9 month old) my spare time has been at a premium. as far as the bigger builds I hope to share those soon.
One of these large side projects drove me into researching alternative waterproofing techniques and wood sealing. I kept running across this thing called poor mans fiberglass.
This 'poor mans fiberglass' is an old boat deck sealing technique (and used else where) where bare wood is sealed by gluing a fabric to the surface and then painting the fabric. The glue should be water resistant and the paint an exterior grade water resistant as well for best results.
And yes Technically this is not fiberglass at all. What is commonly referred to as fiberglass is a polyester epoxy resin and cloth composite.
Step 1: What Is the Scope?
1. Test out this old school compositing technique on a small scale to see how difficult, and durable it is before I use it on something large (only hint ill give is you can sleep in it and it has 2 wheels)
2. Hope to expose people to composites in a broad sense; to think outside the exotic composites that get all the media attention: carbon fiber space age bla bla. (Lets face it plywood is a handy composite)
3. Showcase how useful paper craft can be. It is often overlooked as an engineering/ prototyping material. (I will admit I've made this mistake.) It is a cheap and readily available media for quick prototyping and even construction of 1-off pieces.
4. Most importantly we had a small cooler that was not very efficient with usable space and I felt an engineered fix was in order.
Enough talk, So lets get started!
Step 2: Find Some Stuff
-Thick card stock material
- Fabric Scraps
- Wood glue (BondTite II)
- Razor knife and or scissors
- Hot glue and glue gun
- Exterior Paint
- Paper for template making
I salvaged around the house for supplies so had no cost in this build if I had to guess having to buy EVERYTHiNG might run you $20.
For my Card stock I used an old gift box my wife was going to toss out.
An old t-shirt and pillow case were sacrificed for the fabric.
The bond tite glue I already had. If you're not looking for a waterproof build, any PVA white glue should work OK.
For the cost $3 Bond Tite is hard to beat. If you can't locate Bond Tite any water resistant wood glue or Elmer's Glue all PVA should be fine.
Step 3: Get Up on a Plan
I didn't have a plan or templates just stated with eyeballing the height I needed and tracing out the bottom of the cooler with print paper and the top section of the cooler as well.
The paper tracings were transferred to the card stock and cut out again.
Dry fit your shapes as you go and trim as needed.
Step 4: Hot Glue, Need More Hot Glue
Step 5: Float, Fabric, Flatten, Repeat
The complex shape I am trying to coat was a bit messy and took some trial and error to get a feel for being consistently successful.
1: I tried thin coating of glue on the work surface and on the fabric. Letting them tac and pressing together. Knit fabric being more porous was more receptive to this method. Weave fabric not so much. Failure mode in this technic was in trying to smooth fabric to remove air pockets. In so many words it was frustrating a results varied from good to ..... Not so good..
2: The next approach I tried was laying the glue on thick to the working surface and applying the fabric right away. This method was more repeatable and either type of fabric (knit or weave) seemed to work fine.
3: The method that I found to work the best for me was using the steps in 2: above and once the fabric is down, immediately coat the top of the fabric with glue, smooth out. The top coat of glue acts like a lubricant layer when 'ironing out' the air pockets. I found 'floating' the fabric between the 2 glue layers made for more consistent surface adhesion once dry.
Seal those edges! : be aware that most composites will fail at seams, lap over your edges and double coat the seams with glue for better water resistance.
Note on loose knit fabric:
Be careful of stretching loose knit fabric. The tendency is to pull the knot edge and stretch air pockets and wrinkles free. Certain knots may draw back in as they dry and will warp your working piece.
Step 6: Finishing Up and Paint
With this fairly complex shape it took quite a while to complete due to the cure time of the glue. Adding another section of fabric too early you run the danger of pulling your previous work loose and are left with an in repairable air pocket. (Can repair it by starting over....)
Once covered and the glue has completely dried overnight its time to seal the outer surface with paint.
This small scale project I just used what I had; Valspar all purpose spray. If you are doing a large exterior piece I'd recommend an exterior latex paint. With the latex paintYour first coating should be watered down to ensure fabric saturation.
The theory of work here is that the paint is far stronger saturated into the fabric. And vise-versa the fabric has nearly no chance to rot being completely saturated in the paint.
Step 7: Closing Notes
I will admit all though the price is very affordable with this poor mans "fiberglass" it can be very difficult to work with due to the relatively long cure time of the wood glue when compared to 'regular' polyester resin based fiberglass.
For anyone that has wanted to learn to work with "regular" epoxy based composites but maybe intimidated by the cost. This old school "fiberglass" is a great way to learn the lay up techniques (they are essentially the same.) I dare say if you can master this glue and fabric composite, epoxy composites should not give you any problem. And You should feel more confident dropping $30+ for some resin and poly cloth to 'play with.'
After a few water tests I'm feeling good about using this material on my large scale project it will also produce an interesting surface texture that is good because I like my stuff to be custom :-)
Until next time, "Take Chances, Make Mistakes, Get Messy." The Frizz