Oozing, seeping sap

I've made a set of seven back steps of standard pine. I think its treated Pine.
These steps have been in the sun now for six months and I recently sanded and stained them with a commercial decking-stain by Cabots. After applying three coats to all of the steps, I still notice that two knots in one of the steps continues to ooze sticky sap.
I've used turps a couple of times and let it dry, but the sticky stuff re-emerges after a day or two. Doesn't seem to spoil the stain though!
What can I do to stop this happening? It's no good getting goo on bare feet is it?

It sounds like there may be a resin 'pocket' deeper in, by the knots. If so, it'll stop weeping eventually, but your guess is as good as mine as to when.

Most decking stains are designed to penetrate into the timber to provide protection. Not far, admittedly, but it's still how they work. They do not seal the timbers and nor should they.

Personally, I'd simply keep wiping off any excess with a clean rag every so often until it stops seeping. I wouldn't use turps or a solvent, as given enough repeat applications that'll affect the finish. Well... maybe a slight dampen of the rag, but not a wet application. Besides, with luck the seepage will slow down sufficiently to the point where it dries as it exudes, thus sealing any remnants inside. Thorough washing would remove that, prolonging the problem.

Nor would I be overly concerned about touching up the finish straight away; 12 months down the line you'll be starting your yearly re-applications to keep it in good condition, right? ;)

Mind you, I'm looking at this from a 'personal use' scenario. I'd go a different path if it was 'for sale' or there was a deadline by which time it had to look right, and even then it'd probably be a compromise I'd not be particularly happy with.

Quote:

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Originally Posted by Skew ChiDAMN!!

It sounds like there may be a resin 'pocket' deeper in, by the knots. If so, it'll stop weeping eventually, but your guess is as good as mine as to when.

Most decking stains are designed to penetrate into the timber to provide protection. Not far, admittedly, but it's still how they work. They do not seal the timbers and nor should they.

Personally, I'd simply keep wiping off any excess with a clean rag every so often until it stops seeping. I wouldn't use turps or a solvent, as given enough repeat applications that'll affect the finish. Well... maybe a slight dampen of the rag, but not a wet application. Besides, with luck the seepage will slow down sufficiently to the point where it dries as it exudes, thus sealing any remnants inside. Thorough washing would remove that, prolonging the problem.

Nor would I be overly concerned about touching up the finish straight away; 12 months down the line you'll be starting your yearly re-applications to keep it in good condition, right? ;)

Mind you, I'm looking at this from a 'personal use' scenario. I'd go a different path if it was 'for sale' or there was a deadline by which time it had to look right, and even then it'd probably be a compromise I'd not be particularly happy with.

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Thanks Skew. Not the answer I hoped for but we may have to live with the oozing until I re-stain.

Shellac is used to seal sap veins and knots. No reason why it won't work with the decking oil but no guarantee it will either. Nothing to lose if it doesn't work. As a rule it's used prior to any finish being applied. However, shellac has the ability to stick to almost anything.

Hope this is of some help to you.

Cheers - Neil :U

:no:Still oozing. Leaves a white powdery film even after using a scraper to remove any surface finish.Attachment 508403Attachment 508404Attachment 508405Attachment 508406Attachment 508407Attachment 508408
The last picture (attachment no.6) is 2 weeks after using the scraper (today). It is now 6 months (most in hot sunshine) and the stickiness continues:~
I have tried using Acetone, water, Turps and Shellac a few times but nothing will end the process. I know it's natural and just sap, but the boards must be at least a year old now. As you can see, the steps are not very large and their capacity to continue to hold huge volumes of sap must be ending. Help! What can I possibly do other than to rip them out?
P.S. Note that only 3 of the seven steps have this problem.

Yeah, that's not a good look.

Another option that has occured to me is to paint the tops of the treads with a rubberised (non-slip) black paint. Maybe using masking tape around the edges to leave a clear frame for aesthetic reasons.

In the past I've used a mix of bituminous paint & sharp sand to give a non-slip surface, but there are probably better commercial products available nowadays.

This wouldn't get rid of the resin but would hopefully seal it in more permanently while ostensibly improving stair safety.

I say 'hopefully seal it in' as this strongly depends on whether or not the paint reacts to something in the resin and how well it is bonded to the surface.

Quote:

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Originally Posted by Skew ChiDAMN!!

Yeah, that's not a good look.

Another option that has occured to me is to paint the tops of the treads with a rubberised (non-slip) black paint. Maybe using masking tape around the edges to leave a clear frame for aesthetic reasons.

In the past I've used a mix of bituminous paint & sharp sand to give a non-slip surface, but there are probably better commercial products available nowadays.

This wouldn't get rid of the resin but would hopefully seal it in more permanently while ostensibly improving stair safety.

I say 'hopefully seal it in' as this strongly depends on whether or not the paint reacts to something in the resin and how well it is bonded to the surface.

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Thanks Skew. I had already applied a surface coat of a commercial non-slip coating to all steps. But by scraping it "all" off a couple of weeks ago where the worst step was oozing I thought I would see what happened. It seemed to make things worse by covering that step in the white powdery residue where the gum had "cured" (if that is what is happening).

Can you add a non-resinous wood to the tops of each tread?
Here at 53N we usually staple gritted asphalt shingles to each step tread with a staple gun.
Fully intending to replace them in 5 years as the grit wears off. 30 minute task.

I probably cannot get shingles of the size of these steps, so I am thinking that another thin hardwood layer might seal the Pine below. Then I could stain and apply the non-slip paint. Glued on, not stapled! But will the sap push through a thin layer on top? Even shingles are not likely to be much thicker than about 5-8mm. And maintenance then becomes an issue!

I'm grateful for all the thoughtful advice but first I'd like to try:
1. Wicking the sap on the worst step until it dries out. Soaked rags clamped loosely to the step. Trying to accelerate the natural process!
2. Repeated Shellac (uncut) on a daily cycle for ? many weeks. (I've only tried one application so far).
3. Sanding the worst step back to basics, first, and repeating 1 and 2.