I recently purchased an Underdog for a good cause, Abysmal’s legal fund. I was happy to be able to help out a fellow FC member, and happy to finally try a vape that had gotten great reviews and was not in my log vape arsenal. Dave's designs are artful and caught my eye from his first post with his beautiful wood combinations and styles offered. Being sensitive to chemicals I had some reservations after reading about the adhesives used in the internals, but, after being assured that the glue used to secure the heatport had been eliminated, the silicone was fully isolated and only used on the bottom of the heatport (as per Dave's post here), I felt my concerns had been addressed. Before I continue, I want to say that I have tried to discuss this privately with Dave. I asked him for the names of the adhesives he uses so that I could research them privately and share/discuss the information with him. He would not cooperate. So I have come to the forum with this information and my questions, in the hope that we can discover whether or not these materials are safe to use in this context and so that people have full knowledge of the materials used in the UD. This is not a personal attack on Dave or the UD and its many happy owners. It's simply something that FC and I feel warrants some discussion and investigation. Hopefully it will lead to a better product and that's what this forum is about. I should also say that in terms of vapor volume this unit delivers admirably. After the unit had been plugged in I immediately noticed an off-putting chemical odor from the heatport. As mentioned, I have always been super sensitive to smells, and I dismissed it as nothing to worry about since there had been several reports of the finish used having a smell. I used this vape for three days but the odor seemed to be getting stronger rather than dissipating and I was getting headaches during my vape sessions which is a first for me. This, along with my prior reservations of what had been found in the UD led me to take the unit apart. There are a few things that I found in the UD that disturbed me. One concern is that I found an adhesive being used to hold the plug in that I suspect is Gorilla glue. In this pic, you can see residue of it around the plug area. Dave has indicated "we only use glues that are FDA approved for food contact (like cutting boards, utensils, etc) as a matter of principle." If this is indeed Gorilla Glue, it does not have FDA classification as a food safe glue. It is classified as an inhalation hazard and respiratory irritant according to its MSDS sheet and also has a boiling point of 212 degrees at which point it will melt. You can see in the picture below that this same glue has been used to try and correct the checking in the laminated joints. There is seepage on the inside walls as well. The second concern is the red silicone RTV (also labeled as an inhalation hazard as per most MSDS sheets; we do not know what brand this is) used to secure the resistor and heatport. It appears that it has been used to “glue” in the two layers of insulation material as well as being used to secure the resistor assembly to the heatport, and heatport to the body. My third concern was that the insulation material being used was disintegrating into little flakes around an area that had scorched. The hole in the insulation is where the heating element wires go through it. Note the scorching and flaking around that hole. When I asked Dave about this, he replied that it was “normal for this material to disintegrate and discolor.” My concern is that the silicone is getting hot enough to cause this to burn so what fumes are being produced? Also, why use something that you know will disintegrate and scorch under this application? As stated above, the only thing separating the red silicone from the air path is a glass bead. In this next picture, you can see the gap formed by the wire on the side. The glass bead is actually touching the resistor. This means that the glass will be the same temperature as the resistor and anything touching it will be subject to that temperature. Since that can be above 400 degrees, the silicone, solder, insulation and wires are exposed to those temperatures. The wires right next to the heating element can get hot enough to melt solder. The pic above shows that it was hot enough, on the other side of the silicone, to burn the insulation. So, my concern becomes, is it safe to breath air that goes past silicone that is exposed to that type of temperature? In this picture, you can also see the Gorilla glue like substance on the plug. The last thing that concerned me was that there was charring at the top of the vape that had led to some cracking. Unfortunately, the heatport opening is rather narrow and my camera is not good enough to get a pic of this. My understanding was that the charring is no longer an issue with the new 24/7 core design since Dave was using an air gap internal to the core as insulation which he felt would keep the wood protected. While I have no idea how many hours this was run prior to my buying it, this design is only 4 months old and I ran it for 3 days. It scares me that this kind of charring, scorching and disintegration of the insulation can happen in this amount of time. I’m putting these questions out there in the hopes of getting some answers this time and to pose the question of whether these materials are safe to use in a device we breathe and medicate through. For me, a manufacturer saying, “this is safe” is not enough.