Epoxy repair church finial.

[Rich F.]

This wood finial doesn’t look like much but it is 38 inchs tall and is about 16” through the middle.  The contractor borught it to me with wrapped with plastic and bunjee courds and told me to patch it just enough so it can be gilded but when I took off the plastic, it fell into 4 peices and the inside is complete mush from where the weathervane rod went through and wicked in the rain.  There is big clumps of caulk and even concrete from where painters tried to stop the hole over the years.  Making a new carved finial is not in the budget.  Can this be repaired?  The contractor says it can but I don’t know what he knows about it.  The outside looks almost completely intact but not the inside.  I can set all the parts on end tied with bunjees and it looks perfect, no rot showing.

[Paul Marlowe]

Rich,
With patience and experience of using epoxies, you can probably repair this finial.  You will need to remove the concrete & soft wood, apply borates, dry it out, consolidate the broken edges, apply epoxy patch to these same edges, connect the pieces & allow it to cure.  If there is enough wall thickness you may want to consider installing 1/4" or 3/8" fiberglass rebar w the initial glue up.  Once the finial perimeter is structurally sound & all voids are filled, the inside can be cast using #600 epoxy mixed w washed sand & stone & thickened w fumed silica as needed.  Another option would be to fill the core using epoxy patch #200, mixed at a slightly lower than normal viscosity to allow you to pour the product into the void.  If this is your choice you will need to encapsulate a dry piece of timber or multiple pieces to absorb heat & slow the cure of the epoxy.  This wood insert or inserts should be sound & consolidated prior to inserting into the void, which should be partially filled w the epoxy patch prior to setting the inserts.  The second method will allow easy boring for the weathervane.
Paul   

[Chicago]

Maybe this post should have gone to the porch column topics, but Paul Marlowe mentioned dissapating of heat buildup when you pour.  I tried to do a pour for a turned porch base or pedastal, and the pour almost caught fire, it was smoking and the epoxy cracked so that the work was ruined.  I did the mixing exactly.  I was doing too big of a pour and I did eventually figure it out from trial and error using small pours.  What I would like to know is there a formula for volumes that will tell just how big a pour can be done safely??

[Paul Marlowe]

Chicago,
There is no precise formula that I know of.   A guide you should consider is not to exceed applying epoxy more than 1" thick, unless there is a perimeter of thick wood around it, wood imbedded into it (inserts) or sand & stone used as a filler.  The sand & stone method is described in the technical data sheet for the #600 epoxy.  These techniques allow you to apply epoxy much thicker because the heat that is generated during the curing process will be absorbed by these fillers & or the wood mass.   

Remember not to allow large volumes of mixed epoxy to sit alone without the proper use of one or more of these heat absorbing materials.  With this knowledge & a patient professional approach to all epoxy applications, this problem should never occur.  To pour in small lifts as you mentioned is also an option.
Paul