Wood-Epoxy Repairs, stile ends (final)

Wood repairs for sashes, frames and sills.
bobyapp
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Wood-Epoxy Repairs, stile ends (final)

Postby bobyapp » January 16th, 2012, 1:28 pm

Author: Bob Yapp
Contributors:
References:

Title of Treatment: Selected Architectural Epoxy Repairs
Class of Treatment: [ ] Maintain, [ ] Stabilize, [x] Repair, [ ] Upgrade, [ ] Exception
Type of Treatment: [ ] Traditional, [ x] Modern

Condition to be Treated:
Minor wood rot on bottom ends of stiles.

Description:
Determined if minor rot on ends of both stiles of a double hung sash do not need wood Dutchman repair and epoxy is appropriate. The rot has not affected the mortises and is less than 1/2" in depth. The inexperience worker should get training or at least try a few sample repairs to learn effective techniques.

Typical Procedure:

1. Scrape away any paint residue in area to be repaired.
2. Lightly blow out any loose rot on the bottom end of the stiles with compressed air. Do not dig out any rot that can't be lightly blown out with the air.
3. Thoroughly mix the two part liquid epoxy.
4. Using a large syringe, inject the liquid epoxy deeply into the affected areas and keep doing so until the wood will no longer accept more.
5. Immediately, thoroughly mix the two part putty.
6. Fill the rotted voids deep into the affected areas by pushing the putty into the rot. Be sure to fill the entire void. The final fill should be "proud" of the bottom end of the stiles to ensure more putty does not need to be installed after shaping.
7. Allow to cure completely according to the manufacturer's instructions. The putty and liquid will cure and adhere well to each other. If a faster cure is desired, use a heat gun on a medium setting and blow the warm air over the putty for 15 minutes with a 30 minute rest and then again for 15 minutes. Epoxy cures based on a chemical reaction creating heat and the heat gun accelerates this process. Do not burn the putty or allow any bubbling on the surface as this will cause the putty to weaken and fail. If done properly you can cure the putty/liquid epoxy for priming in about one hour.
8. After curing, hand shape the epoxy putty with tools of choice such as block planes, chisels etc.
9. Once all shaping is done it is critical to drill at least three 1/16" diameter weep holes up through the end of the stile well into the unaffected wood beyond the repairs. This will allow any moisture migrating into the wood above to migrate down through the epoxy repair instead of trapping it above the repair and causing further rot.
10. Prime the epoxy surfaces.
11. Carefully re-drill the weep holes after priming and painting to assure they are clear.

Materials:
• Epoxy consolidant, two-part liquid, architectural grade designed for the repair of decayed wood in architectural elements
• Epoxy filler, two-part putty, cellulose base epoxy, compatible with the liquid epoxy, architectural grade.
• Primer, oil-based alkyd resin

Quality of Results:


Best Work:
Epoxy materials encompass the entire rotted void and are tooled flush with adjacent surfaces. three 1/16" weep holes are in place. All properly cured putty is entirely in the rotted voids and flush with no voids. Weep holes are re-drilled after priming and painting. The patches cannot be seen after painting.

Inadequate Work:
Not enough putty was installed and so it is not flush with the original surfaces. Weep holes were not drilled in the bottom of the stiles. The entire void was not filled with liquid and putty. Water based primer is used.

johnleeke
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Re: Wood-Epoxy Repairs, stile ends (draft)

Postby johnleeke » January 17th, 2012, 7:05 pm

Does this method require coat of oil primer on the epoxy surfaces?

That needs a step. Should it be at the end?

Otherwise, looks like this one is ready to go.
John
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Bob Yapp
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Re: Wood-Epoxy Repairs, stile ends (draft)

Postby Bob Yapp » January 18th, 2012, 1:36 pm

"Carefully re-drill the holes after oil priming and painting to assure they are clear"

Add alkyd based oil primer to the materials List

Then

Let her rip!

johnleeke
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Re: Wood-Epoxy Repairs, stile ends (draft)

Postby johnleeke » January 19th, 2012, 9:52 pm

OK, I added a couple of steps to cover clearing out the weep holes.
John
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Paul Marlowe
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Re: Wood-Epoxy Repairs, stile ends (draft)

Postby Paul Marlowe » August 25th, 2012, 2:36 pm

My approach to applying epoxy to stile ends is different than Bob's. So much so that I'm not sure I should post it. Any thoughts?

johnleeke
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Re: Wood-Epoxy Repairs, stile ends (draft)

Postby johnleeke » August 25th, 2012, 3:04 pm

Paul, if your approach is really different, then click on the "New Topic" button and post your message starting a new discussion.

Paul, here are two other wood-epoxy repair discussions I'd like you to take a look at:

http://ptnresource.org/WPSC_forum/viewt ... ?f=16&t=63

http://ptnresource.org/WPSC_forum/viewt ... p?p=92#p92
John
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http://www.HistoricHomeWorks.com

johnleeke
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Re: Wood-Epoxy Repairs, stile ends (draft)

Postby johnleeke » August 25th, 2012, 3:13 pm

Bob:

In Materials you have:

"Epoxy filler, two-part putty, cellulose base epoxy, compatible with the liquid epoxy, architectural grade."

Are you describing the Abatron WoodEpox product? Do you mean that the epoxy putty has cellulose in it or it is made from cellulose? Or, do you mean that it is made for repairing wood, and it's the wood that contains cellulose?
John
Standards Co-Founder
Standards Editor

http://www.HistoricHomeWorks.com

Paul Marlowe
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Re: Wood-Epoxy Repairs, stile ends (draft)

Postby Paul Marlowe » August 26th, 2012, 6:54 pm

Replying to Bob Yapp's post with a slight variation to some of the techniques, but likely having similar results.
2.
Lightly blow out any loose rot on the bottom end of the stiles with compressed air. Do not dig out any rot that can't be lightly blown out with the air
. HEPA vacuum used for dust control. Liquid borates may sometimes be used as a spec. here.
4.
Using a large syringe
A 1/2">1" chip brush or squirt bottle will also work. Sash secured vertically with the decayed stile ends on top, provides for the best penetration and control of the epoxy consolidant.
6.
Fill the rotted voids deep into the affected areas by pushing the putty into the rot. Be sure to fill the entire void. The final fill should be "proud" of the bottom end of the stiles to ensure more putty does not need to be installed after shaping
.
The alternative to this one step process of overfilling is using a flush fill which will normally need a second application of epoxy filler only. If multiple areas are being filled such as on other sash, a second touch up coat of filler might be acceptable because the tooling will be easier and there will be less potential damage inflicted on the surrounding wood while tooling the cured epoxy filler.
7.
Allow to cure completely according to the manufacturer's instructions. The putty and liquid will cure and adhere well to each other. If a faster cure is desired, use a heat gun on a medium setting and blow the warm air over the putty for 15 minutes with a 30 minute rest and then again for 15 minutes. Epoxy cures based on a chemical reaction creating heat and the heat gun accelerates this process. Do not burn the putty or allow any bubbling on the surface as this will cause the putty to weaken and fail. If done properly you can cure the putty/liquid epoxy for priming in about one hour.
Some systems are formulated to cure slower to increase the penetration plus enhance the bond and durability of the repair. Understanding the desire for quicker repairs in order to better compete in the restoration market and lower the cost of window repairs is common, but as Bob mentioned care must be taken otherwise failure could be premature. I prefer to plan for delays with the epoxy cure and set up to do some of the other work required whenever possible.
8.
After curing, hand shape the epoxy putty with tools of choice such as block planes, chisels etc.
It is important to include sanding, which can be the only means of tooling, but if not it is normally done to abraid the surface prior to painting.
9. Once all shaping is done it is critical to drill at least three 1/16" diameter weep holes up through the end of the stile well into the unaffected wood beyond the repairs. This will allow any moisture migrating into the wood above to migrate down through the epoxy repair instead of trapping it above the repair and causing further rot.
This I have never done and see no need to because a drain plane is unknown etc. I could discuss this further another time if needed, but I will say it is the same theory of the 19th century relish allowing moisture from above to be removed. The reason for the relish is to stop the rail from splinting out during milling.
• Epoxy consolidant, two-part liquid, architectural grade designed for the repair of decayed wood in architectural elements
I assume the term architectural grade epoxy is the same terminology as non-structural epoxy. Different systems using different terms to describe the same thing.
• Epoxy filler, two-part putty, cellulose base epoxy, compatible with the liquid epoxy, architectural grade.
The key words here might be flexible epoxy.
• Primer, oil-based alkyd resin
Oil based primer or finish paint will dry slower than normal because the epoxy won't allow penetration like bare wood will. They are being phased out I believe and don't hold their color as long. Water based primer and finish paint have the problem of drying to fast, but it seems that is what we are or will be left with.
Inadequate Work:
Not enough putty was installed and so it is not flush with the original surfaces. Weep holes were not drilled in the bottom of the stiles. The entire void was not filled with liquid and putty. Water based primer is used.
The Weep holes and water based primer specs. have already been mentioned above.


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