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Laying up a fiberglass body tube

by George Gassaway, with Terrill Willard & Ed LaCroix

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Japanese tissue (shiny side down) taped onto paper
so pattern can be printed onto it. Print as a mirror image
if you print things like name or numbers onto the tissue

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Full size 2-wrap pattern template for Fiberglass Cloth

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Fiberglass cloth pattern templates cut from poster paper. 2-wrap (blue) & single-wrap (green). Notice the holes cut to allow for using marking pen to mark reference dots onto the cloth.


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40mm Mandrel on 1/2" PVC pipe based holder.
The holder's end pieces are not glued, they fold down for storage.

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Mandrel, holder, and Mold Release spray can.

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Terrill Willard applies mold release spray. Several coats are used.

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After using marking pen to apply reference dots onto cloth, outer edges
of cloth are cut out using a fresh single edged razor blade.

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Cloth after cutting. Note the reference dots. This particular tube was made for an egglofter, so there was no extension at the end of the cloth for a 10.5mm engine mount.

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Draw a parallel reference line onto the mandrel. Do not start the epoxy mix until you have everything ready, including the tissue. After mixing, pour the epoxy into a very shallow and wide container such as a 3" mailing tube endcap (bottom of photo). This will reduce the "exotherm" reaction so the epoxy does not start to self-cure as fast as it would if left in the mixing cup. Apply epoxy along the marked line. Drape the fiberglass cloth over the epoxy so that 25% of the cloth drapes over the other side, so the reference dots are along the mandrel reference line. Brush the "Far side" down, then after getting back to the reference line, continues onwards by rotating mandrel and brushing epoxy.

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Continuation of brushing, done by Ed LaCroix. Red dye was added to the epoxy before mixing. The Red Dye was not for the tube color, but to be able to see how much epoxy there is. Do not skimp on applying the epoxy, excess will be removed later.

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After brushing epoxy over the first wrap, the remaining epoxy on the mandrel layup is usually enough to complete the rest of the layup without applying more epoxy. Care is needed to keep the cloth from being distorted too much. The reference dots help in keeping the tailcone part of the cloth aligned.

Not shown - After the cloth layup is complete, as much of the epoxy needs to be removed as possible. Use a roll of toilet paper, and press it sideways against the mandrel like a roller. Press onto the toilet paper roll as you roll it, to force epoxy away from the cloth and onto the toilet paper. Remove the epoxy-saturated tissue and continue on with "fresh" tissue on the roll. The red pigment in the epoxy really comes into play here to help show how much epoxy is being removed. When there is no longer any "pink" epoxy transferred onto the toilet paper roll, you're done.

Care does need to be taken not to inadvertently distort the fiberglass cloth layup when doing the above process.

 Not shown - Mix up a little more epoxy (no pigment needed), to fill the pores in the Japanese tissue. For the tailcone tissue, main body tissue, and engine mount tissue, lay each onto a scrap piece of smooth plastic (such as a page protector or thick unwrinkled garbage bag). Lay the tissue shiny side down. Use a "Squeegee" to force epoxy into the tissue, then use the squeegee to scrape off all the epoxy you can, so the tissue is "damp". Apply the tissue to the mandrel, shiny side OUT. You may need to brush a little bit of epoxy onto the overlap seam area.

Note - For a Squeegee, I use a piece of .04" thick plastic, about 2 x 3" long, with the 2" wide end used for the squeegee. I round the corners so they do not dig into the tissue and rip it. Also, I sand the ends rounded.


The completed layup. The marker reference line on the mandrel
can be seen as well as the overlap of the green tissue.

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