Cabot's SPF continued

[PressurePros 248]

I received this letter from a customer. Before I make any type of assesment or comment I would like to hear your input.

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Hi Ken,

I thought you would be interested in Cabot's response to the SPF peeling off of my Ipe deck. They said

"The tape pulls revealed a significant amount of wood fiber on the back of the stain samples. Dead wood fibers on the surfaced will interfere with the durability of the SPF Deck and Fence Finish. The stain bonds to the loose wood fibers and as they break free from the surface the stain will lift and peel with it. It is important to remove any raised grain or dead wood fiber prior to coating by lightly sanding with 80-100 grit sandpaper."

I would be interested to know if you find their explanation credible. My deck was power washed using Cabot's recommended deck cleaner prior to staining. In your experience are loose wood fibers an issue with Ipe?

Any advice you could offer would be greatly appreciated.

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Is the Cabot's rep still here?

[CB works 14]

James,

I would love to see those Commandments when you're done with them. I looked at my first deck of epi yesterday that looked like crap. I have no experience with exotic woods. The stuff he had on there was called EPI MAGIC from WOOD GINIE. The deck looked much like the ones in Ken's pictures, all filmed up and chipping. With the great network of knowledge on this bb I think I can do this job.

Thanks,

Christian

[RPetry 564]

Oh boy. First secret handshakes, then banditos coming out of the woodwork. Followed by the new splinter group, the BDA.

Now Diamond Jim's 10 Commandments of Exotic Wood. This should keep the Grime Scene wood boards jumpin' for a while!

[Beth n Rod 1,279]

Acetone acts like an emulsifier with the woods components (namely the extractives which play an important role in the Ipe's color, and permeability to preservatives) and allows a product to combine with the extractives until the acetone evaporates and the extractives return to their original state holding on to the product as well.

Sort of like super glue: how it makes things like plastic become soft and somewhat like a liquid then it rehardens with the other elements attached to it. Same process.

It is important to remove any raised grain or dead wood fiber prior to coating by lightly sanding with 80-100 grit sandpaper."

This is the most disturbing to me...100 grit!?!?!? This is comparable to furniture finish smoothness and removes enough wood to close up the pores. I personally never use more than 80 grit on wood, 60 as a rule for better penetration.

I had one guy who insisted on going over the wood he just hired us to sand with 100-110 grit and told my crew I didn't know what I was doing. Outdoor wood needs to be more open in order to absorb product as deeply as possible otherwise the finish will not last as long as it should. He is finding that out now.

Rod!~

[PressurePros 248]

Would acetone be an advisable prep for all sealers?

[Beth n Rod 1,279]

It's over kill for other woods like cedar, redwood or ptp. The extractive content of these woods is not as high as Ipe. Also, since these are concidered soft woods by definition and are non-porous, they rely on the fibers to conduct water and sap up and down the tree so introduction of a sealer is easily absorbed and migrates into the substructure (like a wick).

Does this help?

Rod!~

[CB works 14]

Rod,

In what situations would you need to sand epi? Or is it prep that you need to do on all the wood after striping it? Do you need to go with some other sanding technique after hiting it with the 80 grit?

Thanks,

Christian

[PressurePros 248]

It's over kill for other woods like cedar, redwood or ptp. The extractive content of these woods is not as high as Ipe. Also, since these are concidered soft woods by definition and are non-porous, they rely on the fibers to conduct water and sap up and down the tree so introduction of a sealer is easily absorbed and migrates into the substructure (like a wick).

Does this help?

Rod!~

actually, no. What I was asking is, is acetone an advisable prep for all sealers used on ipe. Great info, Rod. Where do you learn all of this stuff?

[Beth n Rod 1,279]

Side note for hard woods in general> have you noticed that some boards different from the rest do not take a finsh well or at all?

Yes. This is due to one of two things: either the extractive content of the wood or in other cases the direction of the vesscular movement when the tree was cut down (either up or down) and will either aid or hinder absorption.

The first: extractive content is contigent upon the cut of the wood in relation to the heartwood as to its age and the sapwood it may be close to. The older the wood in Ipe's case the darker the heartwood. The opposite can be true for newer wood where it is lighter in contrast.

The second: Imagine a billows but in the sense of being inside a tree. as it expands, it is taking in water and as it contracts (depending upon which direction up or down) it pushes the water out of the area. Sort of like cholesterol in humans, trees can develop Tyloses which block the pores making it difficult to get anything into it.

What is your understanding of it?

Rod!~

[Beth n Rod 1,279]

Professionally, I would say yes to any product whose viscocity is high and is generally designed to be surface resident instead of substrate resident.

btw Ken... Have your downloaded the USDA Forest Products Laboratories Wood Handbook? Its a great resource for understanding the dynamics and characteristics of woods. ;)

Rod!~

[Beth n Rod 1,279]

In what situations would you need to sand epi? Or is it prep that you need to do on all the wood after striping it? Do you need to go with some other sanding technique after hiting it with the 80 grit?

We have not found many situations for the need to sand Ipe in general. The most we will do like after stripping is to defur the wood by using a defurring pad ( check with Tom Vogel @ ACR Products http://www.acrproducts.com) on a 7" buffer w/variable rpms. This helps to remove the crushed velvet look and restores the smoothness without over heating the wood and causing it to 'polymerize' the resin making penetration of a sealer even more difficult.

Sanding we have attempted in cases like trying to remove mineral stain rings from planters placed on a deck have been futile. I have other options I am looking into for this but have some fastener corrosion issues to resolve first.

Rod!~

[CB works 14]

We have not found many situations for the need to sand Ipe in general. The most we will do like after stripping is to defur the wood by using a defurring pad ( check with Tom Vogel @ ACR Products http://www.acrproducts.com) on a 7" buffer w/variable rpms. This helps to remove the crushed velvet look and restores the smoothness without over heating the wood and causing it to 'polymerize' the resin making penetration of a sealer even more difficult.

Sanding we have attempted in cases like trying to remove mineral stain rings from planters placed on a deck have been futile. I have other options I am looking into for this but have some fastener corrosion issues to resolve first.

Rod!~

Thanks,

I have a variable speed buffer, I'm just not sure how slow to use it to defur and not get too much heat. 1000rpm?

Will the furring occur from the striper application? Or is it something that happens from wood that is exposed for too long with failed stain, as in the case of the deck I looked at? Sorry for all these questions. I am just brand new at this and want to learn (I know nothing at this point). So many questions!!

Christian

[Beth n Rod 1,279]

Strippers will cause furring, exposure to UV for long periods and then being cleaned with a caustic will cause them too.

It is a remediable condition.

Sanding will create more heat than the defurring pads. Defurring pads actually pull the loose fuzz off the wood, while sanding abrases the entire surface with friction. In the case of sanding an area of Ipe or other hardwood with a grit higher than 60, you would then need to use acetone on the area to allow for better performance of the product you are applying. The result will be more even and less shiney than otherwise.

Rod!~