Sealing Test Results for Yellow Birch
 

This is a test of the effectiveness of four sealers applied to yellow birch lures. The sealers are:

1. ESP 155 epoxy(*)
2. 75% Low V epoxy(**)/25% acetone
3. 60% Helmsman (***)/40% mineral spirits
4. 50% Tung oil/33% turpentine/17% Helmsman (***)

(*) ESP 155 is a commercial penetrating epoxy containing 24% Xylene
(**) Low V is a low viscosity epoxy consisting of 100% solids
(***) Minwax Helmsman spar urethane, satin sheen, quart-can

I chose these four sealers to test because they were products I collected over the past few years but I never compared them objectively.

Point of Testing
 

Specifically, I wanted to look at the following (in order of interest):

• See which sealer best protects lures from punctures in the surface of the wood
• See which sealer best protects undamaged lures
• Compare drying times of sealers
• Compare cost of sealers

Lures Used in Testing
 

Some info about the lures created for the test:

• Turned from same piece of yellow birch lumber
• Turned to same dimensions on Vega (.9” width, 4.5” length, rear taper to .375”)
• 90° cut on face
• Through-drilled with 7mm belly hook hole
• Average lure weight: .993 oz
• 33 lures were turned:
  - 3 were left raw (not sealed or painted)
  - 6 were left unsealed but primed and painted (3 were punctured, 3 were left undamaged)
  - 6 were sealed with ESP 155 (3 were punctured, 3 were left undamaged)
  - 6 were sealed with Low V acetone (3 were punctured, 3 were left undamaged)
  - 6 were sealed with Helmsman/mineral spirits (3 were punctured, 3 were left undamaged)
  - 6 were sealed with tung/turpentine/Helmsman (3 were punctured, 3 were left undamaged)
• Because my main interest was seeing how well the sealers protected against punctures, I primed & painted the lures to be a little more realistic about the additional water-impermeable layers we put on real lures. Priming & painting consisted of:
  - 2 coats of 50% Zinsser Cover Stain/50% naphtha dip-primer
  - 1 coat of Valspar spray primer
  - 1 coat of Valspar spray lacquer
• Half of the lures were punctured after sealing/priming/painting to simulate bluefish teeth and hook point damage. Each lure that was punctured received 8 identical holes from the very tips of #15 twist nails at a depth of ~ 3/32”; a jig was used to place holes in the same locations on each punctured lure.

Sealer Application
 

See attached for info about how sealers were applied and how much weight they gained immediately after sealing.

Sealer Drying Data
 

Immersion Testing
 

After puncturing half of the lures, they were placed in an eel bag and submerged in saltwater. They were removed at time intervals to be blown out with compressed air and weighed on a lab balance to record the amount of weight gained by water absorption. It took an average of 20 minutes to weigh all lures and submerge them again. The time interval for the next weigh-in began when they were returned to the water. The posts below contain both data tables and graphs. Graphs are all based on percentage of lure weight gained over time. Each value represents an average of three lures.

Water Gain of Punctured Lures
 

(This was the testing I was most interested in)

• Attached summary table shows increase in lure weight (in ounces, grams and percent of original weight) over time for PUNCTURED lures
• Attached chart shows increase in lure weight (in percent of original weight) over time for PUNCTURED lures

Water Gain of Undamaged Lures
 

Sealer Cost Comparison
 

The attached table is a comparison of the costs associated with each of the four sealers, as well as the dip-primer I use. Costs are compared by $/ounce, $/cup, and $ to initially buy components if you needed all the components. NOTE that the costs associated by volume for epoxy-based sealers are for one-time usage. This greatly increases their overall cost of use.

Thoughts About the Testing
 

• I was primarily interested in seeing how well the sealers performed over a 6 hour period, which is about the longest I can wetsuit at a stretch these days.
• The difference in the performance of the sealers (as a part of the system) was negligible to my mind – both for punctured and undamaged blanks. The tables do the best job of showing how close they are -- the charts had to be magnified in order to better show the visual separation.
• I have been using ESP-155. My assumption that this solvent-thinned epoxy protected punctured lures better than oil-based or urethane-based sealers isn’t appreciably true.
• With such similar performance, it’s easier for me to give more consideration to other factors. Epoxy sealing is greatly more expensive, so I will not be replacing it when I run out.
• I did not do a breakdown of safety-related issues with each sealer, as I didn’t feel qualified to say anything other than what has been said in other threads: Xylene/xylol and acetone should be left out of hobby plug building. It’s going to be much easier leaving this behind after this test.
• I will move on to sealing with the tung oil solution, primarily because I have an 80 oz jar of it, and it has held up to storage quite well (it wasn’t touched for 18 months prior to this test, and it had only a very light skim on it.)

A lot of work, but I’m glad I did it. Hope this helps someone else out.

Eric

That was informative and fun, thanks.

Thanks Eric. that was a load of work and some great info.

Thank you Big E, for a hobbiest like me, your indepth study really take the guess work out of sealing. It was an area that had very little available info to include weight gains and cost effectiveness. Great study, thanks again for sharing that info.

That was interesting especially when it gets to the cost of the various methods. Every year I seem to do a little less building so have been trying to keep the costs down. I have messed around with using the different epoxies that I had been using as top coats as sealers and i have not noticed any appreciable difference between any of them.

I do like how the epoxies harden the wood. Some epoxies like Etex are a lot cheaper than others like the sys 3 products and when thinned with denatured alchohol they seem to work just as well as a sealer. Nice thing is I can use the same product for sealing and topcoat, and shelf life does not seem to be an issue.

Great breakdown Eric!!! Very scientific!

Eric,

Great job and thank you for sharing the results. Remember what ever we do to seal, paint, look pretty, etc. The goal should always be to have a warrior that gets beat to hell and looks like the following.

Nothing makes me happier than to see my lures beat to hell like this with chunks missing and still fishing well.

Billy

Nice work! With the urethane or tung oil mixes you can always do a second dip for added protection. First dip might not close all the pores
Posted from my iPhone/Mobile device

Very impressive Eric!

Would love to see this done with the other woods used for plugs: AYC, WRC, EWC, pine, etc..

If you do maybe you could take up a collection so that everyone who benefits shares in the expense? I would gladly pitch in.