Tag Archives: Tom Pawlak

Panel Warping

By Tom Pawlak — GBI Technical Advisor

CAUTION: Strip planked projects can warp to the point of being unusable if one side of the wood core is fiberglassed and the other side is left unsealed. Changes in wood moisture content on the unsealed side will cause the project to change shape. The potential for warping is greatest on thin wood-strip projects like canoes and kayaks. The thinner the planking, the greater the risk. Continue reading

Positive displacement epoxy pumps

Big Batch Mixing Methods

By Tom Pawlak — GBI Technical Advisor

Most of us use epoxy in small batches, mixing several ounces at once. This gets the job done 95% of the time. But for some projects, such as large laminating jobs, you may need large batches of epoxy. Before you begin, you should understand what’s involved in mixing big batches of epoxy. Continue reading

Fiberglassing – Shop Tips

By Tom Pawlak — GBI Technical Advisor

Corners that require fiberglassing need to be rounded to allow the fiberglass cloth to conform to the corner. If the fabric you are working with won’t conform to a rounded corner, here’s a tip that may help. When draping fiberglass around a corner, orient it so the fibers are at a 45° angle to the corner. The fibers will conform much better than if oriented at 90°, because they are not bending nearly as much. Continue reading

removing fiberglass

Fiberglass Removal Techniques

By Tom Pawlak — GBI Technical Advisor

Occasionally we receive calls from people who want to remove fiberglass cloth from wooden structures. The fiberglass on the bottom of a stripper canoe has worn out or the fiberglass and polyester on the deck of an older wooden sailboat has delaminated. The techniques described here work well for removing 1 or 2 layers of fiberglass cloth from wood surfaces. Continue reading

primer performance

House Paint Primer Performance

By Tom Pawlak — GBI Technical Advisor

In the past, we’ve recommended applying an alkyd base primer over well-cured, clean, and sanded epoxy surfaces. We wanted to know how this primer compared to the newer, fast drying primers now available. We recently did a study of various house paint primers over epoxy to support the growing number of customers using WEST SYSTEM epoxy for building restoration. Continue reading

scarffing plywood

Plywood Scarffing Methods

By Tom Pawlak — GBI Technical Advisor

There are many ways to machine scarf bevels on plywood panels. The best method depends on how many scarf joints your project requires. If you need to scarf only two sheets of 3mm plywood, using a block plane and sanding block is a good low cost option. If you have a daily need to scarf many panels, a reliable machining method is a wise investment. This article reviews several popular scarffing methods and tools, to help you decide which is best for you. Continue reading

vacuum table

The Vacuum Table

By Tom Pawlak — GBI Technical Advisor

A vacuum hold-down feature can be incorporated into a table to hold individual sheets of plywood in place while you machine scarf bevels. This feature works especially well when using the router box technique described in the scarfing article. You’ll need a fairly large vacuum pump. We use an oilless rotary vane vacuum pump made by Gast, Model No. 3040-V115A. It generates 25 cubic feet per minute (cfm) at no vacuum and 5 cfm at 20″ of mercury. Smaller units may work, but lots of cfm and reasonably high vacuum are required when plywood is warped or rough. A vacuum table will work most efficiently holding down smooth, flat plywood panels. Continue reading

Relief from Fiberglass Irritation

By Tom Pawlak — GBI Technical Advisor

Working with fiberglass fabrics can cause skin irritations ranging from minor itching to a serious rash. It’s caused by microscopic, needle-like fiberglass spindles of that prick your skin. It helps to protect your skin with gloves and long or disposable protective sleeves, but here is what to do if you’re faced with a fiberglass-induced itch. Continue reading

Specialty Tools for Fairing

By Tom Pawlak — GBI Technical Advisor

The Fairing File

My son Matt and I recently built a small stitch-and-glue boat. While fairing the bottom we discovered that hacksaw blades can be modified and used for fairing.

The buildup of fiberglass tape along the chine and keel had caused a low spot in the hull all along the edge of the fiberglass buildup. Filling the low spot with low-density filler was easy, but sanding the cured epoxy with sanding boards was slow work. Experimenting with a new hacksaw blade, we found it easily cut through the low-density filler and occasional high spots in the fiberglass. Continue reading