fiberglass tape question

[dwgriff1]

I am doing some repair on my trailer and want to use 5 inch fiberglass tape on the corner/edges.

I know it can't wrap it around square corners - tried that!

Can I wrap the tape so it will work with a 1/2" round over? 3/8?

I am going to be using poly resin and I am going to paint over the glass.

dave

[Ageless]

Depending upon the weight of the tape. If it's a thin, lighter tape, a 1/4" R should suffice. As you are working a compound radius you'll need to work it to keep away from puckering.

If you have a work suface where you can wet out the material first is an easier way to get it to lay.

[mikeschn]

Andrew mentioned something about that as a possibility for the outside of the Pico Light... I thought he had a link, but I can't find it now. Maybe he'll see this post and chip in?

Mike...

[dwgriff1]

Ageless:

Wet it with thinner? Acetone or such? Surely not water.

dave

[Ageless]

"wetting out' cover your work surface with plastic. Soak the tape with resin then fold it in 3 layers for ease of handling.

[afreegreek]

you can also use 45-45 bias tape or cut your own out of cloth but unless you're trying to add structural strength I'd go with matt. it will form around tight compound curves a lot easier than woven cloth. I've had good success going around radiuses as small as 1/8" with 4 and 6 ounce cloth going with the warp and 1/16" on the bias. you can also stretch plastic film over it and hold that down with tape. just make sure the styrene won't eat the plastic.

[dwgriff1]

I have a good sized roll of tape that I may not use after this conversation!

Thanks for the help, the information was what i was looking for.

dave

[dwgriff1]

I have a good sized roll of tape that I may not use after this conversation!

Thanks for the help, the information was what i was looking for.

dave

[angib]

You really have to do some trials on similar scrap pieces as suggesting an answer at this distance ain't easy.

It might be easier to get lighter glass tape rather than fight thick stuff - if that's what you've got. A couple of offset strips of lighter tape are actually stronger than a single thick tape, and is certainly easier to apply. It will also have a less noticeable edge if you want the repair to be less obvious.

If you want to do a really neat job, get 'bi-axial' glass - this has the glass strands at 45/45 instead of 0/90 and you just would not believe what complex shapes this will conform to, without any puckers - applying one piece of glass to the end of a football is perfectly possible. Bi-axial (some pros always say 'bi-sexual'...) is a specialist product and is only usually available in cloth, not ready-made tapes.

Sometimes it's easier to apply 'wet' glass - lay some strips of plastic sheet (you have to test it for resin resistance) down on a workbench, put tape on top of it and wet that out with the resin. Paint resin on the trailer, pick up the plastic/glass combo and lay it on the wetted-out area. Peel off the plastic, stippling down the tape. This way is pretty essential on any overhead work.

Andrew

[aggie79]

If you want to do a really neat job, get 'bi-axial' glass - this has the glass strands at 45/45 instead of 0/90 and you just would not believe what complex shapes this will conform to, without any puckers - applying one piece of glass to the end of a football is perfectly possible. Bi-axial (some pros always say 'bi-sexual'...) is a specialist product and is only usually available in cloth, not ready-made tapes.

Andrew

Jamestown Distributors has some 6" bi-axial tape x 15 yards for ~ $30.

[starleen2]

Personally - I'd use fiberglass tape instead of trying to cut off some strips of biaxial fiberglass cloth. The tape has sealed edges and will prevent excess stringing of fiberglass threads - How do i know? i thought I could save a few $$$ and cut my own strips - wrong! The sanding alone for the removal of stray strands was enough. Do yourself a favor and use the tape - whatever type you may choose for the edges.

[Larry C]

I stopped using fiberglass tape for kayak building a long time ago. It is much easier to make your own. If you dont already have a fabric cutter and cutting pad, pick one up a Walmart. The cutter looks like a pizza cutter and the pad protects the blade as you cut.
Buy some 4 oz Fiberglass cloth, roll it out onto a table that is covered with something that wont catch the cloth. I use paper. Lay a straight edge on a diagonal accross the cloth. Put the pad under the cloth and cut on a 45* angle accross the cloth, moving the pad as you go. Repeat this process for thr strip width you want, usually 3" or so is good.
Lay the strips on wax paper and wet them out with epoxy resin. I don't use polyester on wood. You can pick up the wet strip and lay it on the project or pick up the sheet of wax paper and transfer the strip to the project, and peel off the waxpaper.
When you cut plain weave cloth on a bias, there will not be ANY strands coming off, and the strip will follow the sharpest curve with ease. The edge of fiberglass tape becomes thick and rough when cured that must be ground off if you want to hide it. Bias cut strips are perefectly level. Your strips wont be much longer than 30-40" so over lap each new strip about 1.5" or 2". Fill coats on 4 oz glass will bury this quickly.
There are some advanced methods that make the finishing even easier, but if your just painting it, I wont go into that now.
As with anything you haven't already tried, there is a learning curve. Practice on some scrap. If you do decide to use the tape, lay out the length you need and with a helper, stretch the length of tape. This helps smooth the edges abd save a lot of grinding/sanding, but tape will never follow curves like bias cut strips.

Larry C

[Corwin C]

+1
on the use of bias cut strips. They will go around compound curves and odd corners that tape could only imagine. Handle the strips with care and you shouldn't have any stringing of the fiberglass.

I personally have never tried the plastic wrap idea (but I'm going to try it on my next project)...should work, I'm just wondering how much the plastic distorts the surface (harder to fill?)

[Ageless]

In 35+ years in Tooling; used tape only for flat surface repairs. Everything else was cut 45 degrees from 6' wide rolls.

[afreegreek]

+1
on the use of bias cut strips. They will go around compound curves and odd corners that tape could only imagine. Handle the strips with care and you shouldn't have any stringing of the fiberglass.

I personally have never tried the plastic wrap idea (but I'm going to try it on my next project)...should work, I'm just wondering how much the plastic distorts the surface (harder to fill?)

i've made patch repairs using 6mil vapour barrier and smoothened it out with a squeegie then taped the perimeter down so it won't curl. once the epoxy is cured the surface is near perfect and the edges of the epoxy are feathered in better that not using plastic. it seems to pool the resin in the little low spots in the weave too. no second application to fill the weave. like anything though it takes a little practice and experience to know what you can get away with.