I went to Bunnings to get a product to skim bog a coffee table, I was offered your Builder’s Bog

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Good afternoon, I’m in Australia and when I went to Bunnings to get a product to skim bog a coffee table, I was offered your Builder’s Bog.

Someone on a furniture painting page I follow confirmed that this was the correct product. It now seems likely that this is not the right product. No one told me you couldn’t use it over a painted surface and I’ve used the smallest amount suggested of the hardener, and it’s cold here.

It’s been sitting for two weeks and doesn’t really seem to have hardened properly despite being put in the sun every day and brought in when the heater is on at night. You’ll see that in some areas where I’ve tried to sand it off, it’s fine, and in other areas, it’s just coming off in chunks. I’m using an electric detail sander and it clags up the sandpaper. At this point, when I scrap it off the sandpaper, it’s very hard, so obviously head does help. I’ve used your builder’s bog before to fill big holes and haven’t had a problem with it at all.

Anyhow, I’m wondering if you can tell me what to do now please. Is it just a waiting game and it will harden sufficiently eventually, maybe after next summer? Or do I need to get it off with some sort of chemical and if so, what chemical might that be please? It’s extremely difficult to get the stuff off with the sander.

Finally, if you know of a more suitable product to use as a skim bog, that would be awesome too. The problem with this table top is that when I sanded it, it had some sort of parquetry top and it has criss crosses all over the place that weren’t evident until I painted it but are now very evident.

Thanks so much,
Sam (8..6.2020)

Hello Sam

I am very sorry to hear you are having a problem. Firstly Builder’s Bog is designed to go directly onto clean timber. The cross linking agents in the formula are aggressive and will soften any paint until they are consumed in the chemical reaction.

Many paints that dissolve in the uncured Builder’s Bog will upset or prevent the chemical hardening process. A very thin skim (say less than 1\2 a mm) is not advisable either due to loss of the volatile reactants before they have reacted and been captured in the fill.

However, from the photos the colour of your fill looks very light and uneven and I wonder if insufficient red hardener is your problem. Furthermore, it is possible that in last summer’s high temperatures the product itself may have separated, leaving a dryish crust on top and brown liquid right at the bottom of the can. If so this needs stirring in.

Now as far as removal goes, the uncured material will come off with acetone, but no other solvents. Otherwise a paint scraper is another option. Waiting longer and heating are not really helpful at this late stage, I am afraid.

As for an alternative “skim Bog”, I suggest a water based single pack product would work ok for a 1 mm layer, since it will dry quickly and shrinkage in a very thin layer will not matter provided most is sanded off. Thicker fills are where our product is great because the heat generated in the chemical curing reaction makes for a fast through cure without waiting for days for water to escape and evaporate. Selleys Permafill is one.

I hope your table turns out well. I enjoy furniture restoration immensely too.

Regards
Stuart Jordan
Managing Director
(13.4.2020)