Archive for ‘ March, 2014 ’

Modifying the WH1081 Weather Station – Part 2

Following on from my previous post Modifying the WH1081 Weather Station – Part 1 this is part 2 of modifying the station. The issue was that spiders decided to make their home inside the rain gauge sensor housing and subsequently their webs stopped the tipping bucket from tipping, and thus rendered it useless!

The unmodified rain gauge (bottom)

The unmodified rain gauge (bottom)

The method described below, so far, seems to have resolved the issue with 100% success. This involves covering all the possible entry points that spiders may enter. It is good to bear in mind that even the smallest of spiders may enter very small gaps in the casing and once inside they tend to grow, as do spiders, so would be good practice to cover up any size gap or hole.

I used a very fine plastic grille to cover any substantial holes and gaps, glued and sealed in place using a silicone sealant. The smaller gaps were just sealed with the sealant only. The plastic grille was salvaged from an old computer fan finger guard, but any kind of find mesh grille will work as long as it is fine enough to keep spiders out and let the rain pass unhindered.

Plastic grille used for covering holes and gaps

Plastic grille used for covering holes and gaps

The way I went about securing the grille in place was quite straight forward, and should be a long lasting fix. This is how it was done:

Cut a piece of grille slightly larger than the actual hole/gap itself then tack this in place using a gel type super glue. The reason I used super glue is the speed in which it sets. This could be done using other types of adhesive such as an epoxy based adhesive (using epoxy would probably eliminate the need for sealing with silicone also, but would take much longer to apply and set, thus making this take many more hours to complete).

Start by tacking one side of the cut grille piece and let that set. Once set and solid it will be much easier to tack the rest. I simply placed tiny spots of glue about 5mm apart from each other then dropped and centered the grill down over them. Using very slight pressure using a tool (screwdriver/knife edge) I centered it and applied slight pressure down for a few seconds whilst the glue set. I first tried using my finger and the adhesive went right through the grille and stuck to my finger!

Tack one side of the grille and let set before doing the rest

Tack one side of the grille and let set before doing the rest

Here two pieces have been tacked just at one end and ready for the other sides to be tacked

Here two pieces have been tacked just at one end and ready for the other sides to be tacked

Once one side of the super glue tack has dried you can then go about tacking the other three sides in the same manner as the initial tacking. Where you may have lumps/bumps or need to bend the grille around angles just apply a few tacks to one edge, let them dry, then do the other edges. This will make for a much more secure and neater finish.

All sides of grille tacked down and the adhesive has dried

All sides of grille tacked down and the adhesive has dried

Once the adhesive has dried you can trim the edges of the grille to match the profile of the plastic itself, if you want. I did this using a very sharp scalpel but any sharp craft knife/Stanley blade will work fine. You don’t need to do this but I’m anal about theses kind of things!

Once trimmed it is time to apply the silicone sealant around the edges to act as both a sealer for the grille and additional adhesive to keep the grille in place for years (hopefully!) to come. There are several ways to apply the silicone sealant and some are much easier than others. You can either let it rip directly from a large silicone gun, and make a mess in the process! You could squeeze out a small amount onto some scrap something and use a tool to apply the sealant, or you could fill a small syringe with silicone and apply it. That way you will have a much smaller bead and is much easier to apply. I chose the latter and filled up a small 5ml syringe with silicone from the standard gun.

Standard silicone gun with smaller 5ml syringe

Standard silicone gun with smaller 5ml syringe

 

5ml syringe filled with silicone

5ml syringe filled with silicone

Which ever method you use, you want to seal right around the edge of the grille being careful not to accidentally seal the middle part as we need this for the rain water to travel through.

Silicone sealant applied to the edges of the grille over the super glue tacks

Silicone sealant applied to the edges of the grille over the super glue tacks

Now it is time to repeat the process on each and every possible gap and hole that a spider may crawl through.

Using the same technique cover every hole and gap

Using the same technique cover every hole and gap

Once all the major holes and gaps are covered simply apply silicone sealant to the smaller holes and gaps, such as the two clips at the side of the gauge catcher/bucket.

Apply silicone sealant to the smaller holes and gaps directly

Apply silicone sealant to the smaller holes and gaps directly

Apply silicone sealant to the smaller holes and gaps directly

Apply silicone sealant to the smaller holes and gaps directly

Once finished, leave for a few hours for the silicone sealant to dry and you can then reassemble and refit the now spider-proof rain gauge!

The sealed grille after the silicone sealant has dried

The sealed grille after the silicone sealant has dried

Hopefully this should keep the little critters out of the gauge. So far it has been about 6 months since I applied the mod and it has worked flawlessly (as much as is possible for this rain gauge!) but it has been over winter and the soon to approach spring season will be a proper test for it.