We seem to have hit a problem with a conversion varnish we have been using. After a period of time (sometimes a couple of weeks, sometimes months) the clear finish begins to cloud or ‘bloom’..First time it happened our supplier told us we had not mixed it properly and we took them at their word but we have been very careful in following their instructions and have used this product in frequently and in general found it to be fine. We have asked them to analyze the mixture and have been unfortunatley got nowhere. Has anyone else had these problems as any advice at this stage would be most gratefully accepted.
Thanks
Replies
Did this happen on more than one project and. if so, was there any similarity of construction, i.e. the bloom appearing on laminated panel stock vs. hardwood or was each project built from the same lumber (lot) purchased from the same supplier at the same time. I can't speak to the chemistry issues but I have seen this happen before in wood that was not sufficiently cured, all surfaces were sealed and the moisture was escaping to the surface. Can the bloom be eliminated by re-coating of a wash coat of a thinning agent? If so, it is acting like moisture was somehow trapped.
Doug
Most likely, excessive humidity was present at the time this finish cured. It helps to have the finish area or shop humidity level at or below 60 %. Adding a drier such as japan drier and naptha will help avoid this.
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